got this yesterday, lite wood, 12" bass with a oval mid and small round tweet. SE 6bq5 micromatic changer, 23" B&W tube. Condition ok, a littel water damage in a couple of spots, not bad.

I like the size, smallish with the round legs with brass boots.

this will be the 3rd of this chassis, so I know it pretty well now and what to expect. I will get some pics as soon as I find the camera.

What I really like about these old console sets is how you can drive the stereo amp directly off the converter or DV player and get good stereo sound. The speakers are pretty good in these old maggies, beat the daylights out of those little ovals most of the box cabinets come with.

here they are...

opps here there are again

couple more for now

wow you got another one! I seem to attract zenith combos. There was one of these locally but the gal wanted $150 for it in not working condition. I just couldnt pay that much for a bw.

How do the crts seem to hold up in these? All the 21 inch bw sets I have found have almost dead crts. They dont seem to last like the smaller ones.

I have all my combos setup like that. I usually just put a bypass on the tv power switch so i can leave the tv in the off mode which connects the amp to the speakers. Most of the combos sound really good with a clean input.

Hows the flyback meltage in this one?

fly looks very good, so far CRT's have been ok to weak, but all work.
power tranny looks/smells ok.

Both EL84's are shot, as is to be expected. I did not remember seeing a rectifier tube, so I am guessing a doubler circuit. those IIRC have the under the chassis caps which dont seem to hold up as well as the twist locks.

There is some water damage to the particle board bottom left front, I will knock it down and stablize with some epoxy wood filler. I would just cut it out, but its what the wiring diagram is glued to, and I would like to save that.

The size is very nice, should fit into a small room very well. I think I could set up a small flat screen color (boo,hiss) on top for watching color shows, and use the B&W for vintage programing, both using the stereo amp of course.


I will pull the HOT and do a current monitored slow power up just to see what happens. there are a couple suspect caps in the HV circuit that are 50/50 (white tube shaped) I prob should pull the chassis and check for bumble bees or black beauties, as this may be a 60,61 which may have used those instead of the white tubes like the others.

This was a 20$ deal so I had to go for it. With the DVD/converter you get the full remote experience which is very nice, Just need to get a clapper to turn it on and of and I will be good to to.

I considered the use of the aux, but it was a real easy fix on the last one to just add in another RCA input, clip the wires on the waffer switch, and run the new RCA to the remaing channel, now clipped off. That keeps the TV power on switch working AND saves the aux for a CD player.

I have never been a fan of having the woofers setup like that. To much cancellation. I have an rca like that and an one where they both fire front, everything else is the same and the front firing had 5x the bass.

I cant get into any of the old shows. To me its like watching a foreign language movie and dont understand a thing. I sometimes watch the news on my bw if I stand the propaganda at the time.

I have noticed that the filter caps will act shorted and get hot then if you let them cool down they are fine. Its like something breaks loose and they un short.

That's a nice Maggie. I'm diggin the simple "modern" look of the cabinet. Looks like it has the same chassis as mine... I think they used that chassis for several years. I don't think mine has any tubular caps... they're all early generation orange drops and also the brown drops (if you wanna call them that). Mine was playing fine till a filter went south and started leaking AC into the picture.

The CRT in mine tests excellent. The lady that had it previously said they didn't watch TV much... they listened to the stereo mostly. That might explain why the CRT is good and the stereo outputs are bad.

well I hope to get to it soon, but I have to make room. Yea the looks really got me hooked, simple clean, and those brass boots are sweet.

I dont need to fix the stereo amp to check out the TV, so that will be looked at 1st, no hurry on the amp/tuner.

The one you recently had with the "hula" issue... that was a maggie, too, right? And you had another as well... prolly same chassis again I bet. Any more of these sets, and you'll be able to get certified by Magnavox! :yes:

yep exact same chassis, bring that hula on baby I'm ready for you now!!

low b+, turned out to be both the doublers were open, I tacked on a couple, ane replaced some of the ceramic tube 1kv caps (.1, .047, and .001) just because. the .001 was leaky the other were ok.

fired it up, no HV, replaced the HOT,damper,rec, got HV but a odd looking raster, looks like the vert is barely working and the Horz was not full.

checked the vert tubes, the vert osc has a high grid voltage bias should be

-40 but is more like -8.

the plate was way low, but that is prob due to the goofed up bias on the tube. there is a .0051 5% coupling cap that may be leaking (the other side has 250v) so I will replace that with a .0047 (all I have) if it is. if that is the problem then I will order the right part later. I checked the VOT it may need a bypass cap, its not shorted so I jumped on on, no help. So I think its that vert osc. Tomorrow I will check if that is not it then I will break out the scope.

I checked the plate load resistor, ok as is the vert height pot.

The -8 means its trying to osc so hopefully that will be the problem.

hmmm not good news, while checking other stuff in the vert sweep circuit I noticed one of the leads on the vert output autoformer is open, Darn...

no joy on finding a vert output can someone cross a magnavox number to a

thordarson/triad/anything else?

the Magnavox is

320079-3 vertical output (it a autoformer)

I have a Magnavox vertical output transformer that came out of a '60 model 23" B&W console. It has 3 wires and the P/N is 320254-4. You can have it if you think it will work.

thanks for the offer but need a 4 wire. I will try moyer monday to see, I am just looking around to see if I can find a sub part number. Its a pretty darn big autoformer. this is the second one in a month that had a bad vert, 1st the RCA CTC 16 and now this little maggie.

I may end up attempting a fix, maybe get lucky on the break (its not shorted the last leg is open, would be nice if its on the outside and not the inside. there is no evidence of trama to it, but something is up, the two defection windings had be cut and reconnected, poorly I might add, I don't think it is orginal to the chassis.

one more option I am thinking about is gutting a ratty magnavox color set for its CRT and chassis and makng this a color set, I dont really care that it is not original (not exactly a colletor item, at least not now) but I would love to have a color set in this neat little console, esp with the tube amp for sound.

its a 26S04, (got the number over at arf).

That last vert transformer you got at Moyers... was it a pretty fair price?

20$ not bad, I will be calling them in the AM

No joy on the vert out from moyer, No joy on the other lead I got from ARF, so now I will contemplate pulling the tranny and seeing if I can find the continuity break. If I am lucky the break is early in the winding starting from the outside (its on the end, just which in the inner or outer) sorta like those disney chipmonks, the one that got canned it the tomato canning plant. He was in the very last can opened by his buddy, when he got out he just said " I was in the very 1st can you just started from the wrong end".

hmmm since its not shorted, and the only problem is the blanking leg, perhaps I can work around that and get the blanking off the yoke windings. I have seen a couple schematics like that, looks like some kind of voltage divider used to tap the yoke windings. 1st though is I have to see if the vert osc is working, and if not why. I am assuming the blanking being open would not stop the osc, but maybe I just cant see it if its getting blanked out I do get some vert on the raster, but most of the CRT is blacked out, just a smudge of raster about 1/3 high and about 1/2 wide. I don't know enough about the blanking signal to know if this could be caused by the open leg.

ok got full raster now, just re stuffed all the can caps. I have not tried feeding it a signal yet, I know I need the horz sync diodes replaced (one is open) and there is no blanking pulse (vert output tranny on the way).

I think I am going to try open up the existing tranny and see if the blanking circuit wire is just broken right at the output. I just was happy to see the full raster. Need to clean up the shop now that it is working. Since I am new to TV it should be interesting to see how the pic looks with no blanking signal at all, so will replace the horz afc diodes and feed it. This will be a good learning exp as I will see what it looks like when it is bad (so I can diagnose problems like this in the future a little bit better).

weak pic, hard to get a vert lock, squiggly lines (horz afc diodes?).

subbed a new RF amp, no change, pulled the IF tubes all tested weak will sub them next...

dug out a couple strong IF tubes getting a pretty decent pic now, still want to replace those horz AFC diodes (even though it seems locked in ok). The blanking is completely disconnected.

the horz osc seems odd, it was fine then I heard it slow down, lost HV and parts started getting hot. I quickly adj the horz pot and the HV popped back on. It has a new horz osc tube. Guess I need to check the voltage drop across the HOT cathode resistor and see where my current is.


Its like I cant adjust the fine tuneing enough to get a real clean pic. I don't know if that is the lack of blanking or not. Will only be able to tell when I replace that vert out tranny.

well some more fiddling and I get a good clean pic now. If I turn down the contrast I get horz white lines. I assume these are retrace lines due to the disconnected blanking wire from the vert autoformer.

I had to add a 1 meg 10 meg resistor over the 2.2 meg resistor in the vert osc height control to get the vert big enough.

just for grins I put in a couple shot 6bq5s (did not want to put in good ones since I have not recapped the amp), got some sound out of it then hum set in and the rec tube started to red plate. So at least the audio detector is working, but I will need to work on that amp before trying again.

dug out a couple strong IF tubes getting a pretty decent pic now, still want to replace those horz AFC diodes (even though it seems locked in ok). The blanking is completely disconnected.

.

ordinary geranium diodes, or shotkey diodes pulled from a switching power supply secondary side will probably work.

looking better all the time, replaced the horz afc diodes, had to re adjust the horz osc coil, checked the HOT cathode current right on the money (124 ma). I will be adding a cathode fuse later and maybe a B+ fuse as well. pic has a bit of a lnterlace problem, but seems to be settling down. You can work it out pretty well with very careful adj of the vert hold but it is just a little to critical. It seems to be getting better as the tv is used. I dont know what circuit in the set conrols vertical interlace sync phase inverter perhaps?

I will check that tube its a 6gh8 by subing with a working one. other tubes include the sync sep /video output tube a 6eb8.

and of course I can check the various resistor in and around those same tubes.

If someone can explain how the interlace is controled pls jump in.

oh and I made up a nice little cathode checker from a dead octal tube base and a socket from the parts bin, all direct connections but for pin 8 which has two color coded wires with clips on the end. The only problem was it added too much height to the tube and the plate lead would not reach so I jsut used a short jumper for that. bypassed with a 1uf and check with both a DMM and a simpson analog, same readings.

before I go off the deep end the play is to clean all tube sockets and the yoke socket as well, clean the brt/con/horz/vert pots. should have done that 1st.

if that does not help the interlace, then I will do some tube swapping with a working set.

if no improvement I will try some voltage checks although I don't think that will help since it is subtle and intermittent (the interlace comes and goes).

If someone can explain how the interlace is controlled pls jump in.

Vertical sync has twice horiz frequency serrations, and sync separators are essentially low pass filters. In one field of video, the vert sync starts at a regular timed horiz sync pulse, the other field it starts at a halfway point between regular timed horiz sync pulses. The object is to try to avoid the horizontal sync from contaminating the vertical sync pulses and vertical oscillator circuits. If that happens, the interlace gets "line paired" and you lose vertical resolution. Scan lines on top of each other instead of halfway in between. But keeping the horizontal sync pulse out of everything else in the TV set is easier said than done, it gets into most everything. Maybe if the vert circuits use horiz B+ boost, a filter cap is not filtering well enough?

I tried to attache the schematic, it was too big. I will try again later, hope you can point out a possible problem area.

there is a .047 cap coming off the screeen of the HOT to ground, perhaps some kind of decoupler? I do not recall checking that one. It looks like a decoupling network as after the cap there is a 8200 5w resistor then it goes to the 245v B+, the Screen of the vert output is connected directly to the 245v source.

I am guessing the .047 cap will work as a decoupler at the freq of the HOT.

If the cap was bad it would have to be open (if it was leaky I would have a drag on the B+) I will try just jumping another cap and see if it has any effect. It's one of those brown dipped one, and I already had a couple bad one of those (leaky, .22uf 200v). The 400v ones tested ok, but I did not test that one.

all the filter can caps and doublers were replaced. as well as the electrolytic cathode bypass caps .

no change after jumping a new cap on that HOT screen.

think it is time to break out the scope and snoop around. I will check the wave pattern on a good set (same chassis) vs this one, on the grid of the vert output tube. then I will adj the vert hold so I get the over lap, that way I hope I can see what the pattern looks like, and if I can see the diff.

one thing I was checking was the voltages of the vert out, 0 on grid, 22 on cathode, all 3 of these chassis have this result, yet the sams say should be
-2.7 and 15. I have checked both the coupling cap and grid leak resistor, both ok. I tried different tubes, including some NOS (thinking it may have been gassy), I get some different cathode voltages (20-23) but the grid is always 0. I check with a DMM and a VTVM with and with out video signal.

The DMM would show millivolts some neg but very small like -50mv and it would jump around.

Sounds like you may have a leaky coupling or bypass cap in the vertical somewhere. All they need to do is get a tad leaky or off and they cause havoc and all kinds of weird issues. If that cap to the grid is even slightly leaky it will cause that to go positive.
Let me see if i have the schematic for this, do we have a model number?

c36-23-11

the coupling cap checked ok on the heathkit cap tester, but I will replace anyway. (the cap that goes to the grid of the 6EM5)

it does give a cathode current of 36ma, not sure how to check it unless I make up a remote socket with leads to connect up a meter on a 9 pin mini.

or could calcutlate it, I know I have a votage drop of about 21 volts, I will need to check the resistance (its part of the lineairity pot circuit).


22v/591ohms=.037 amps=37ma so seems like it is right on the nose.

finally popped the amp out while I wait on the vert out. sounded crappy, shorted filter cap. I used the dremel tool (looks like a bone saw) and just cut it off in place. I little messy and you need to protect other parts around if you slip, but very very fast and best thing is you leave the underside completly intact. drilled some holes, put in caps, pulled out the guts, put the top back on. I really like the fact that you can leave it all attached down below. The amp is SE with 2 EL84 tubes. I did not care for the single shared cathode resistor so changed it out for separates, upped the values some too to run the tubes a bit cooler. stayed with the orig values on the bypass caps.
(was a 100 ohm with a 20uf bypass, went with 250 ohm and 10uf on each tube). Before the bias was about 7v but now I found 12 on one and 4 on the other , yikes, got some nos tubes and now I get just under 8v on each withing .2v of each other. Sound MUCH better, I was getting all kinds of distortion. Granted changing the tubes would prob have been all that was needed, but I really like to check the bias so a good tube is not ruined by a bad one. The set came with out a MPX subchassis so I will have to search out ebay and see if I can find one, I want the stereo to work on FM.

I also will prob direct wire an input for the TV converter stereo out. The wafer switch is a little funky on this one and I cant seem to make out how to separate out the TV side into two channels like I did on my astrosonic. this wafer switch looks like its made from ceramic and you cant see the contacts, so with out a schematic its hard to figure how they took the single tv audio feed and get it two both channels. The astro was easy you could see the jumper wire in the wafer, I just cut it and installed another RCA jack.


oh the can on the tuner was open as well, loud hum when attached to the now repaired amp. bone saw to the rescue.

replaced the vert out tranny, no more retrace lines. Still have a little bit of an interlace issue, there is a .0051 5% cap on the grid of the vert osc, I picked up a .0051 1% silver mica (I think) that I will replace. Hopefully that will hold it steady, if not I still need to drag out the scope and do the side by side comparison. The audio is a little buzzy (sync buzz) but not too bad, beside I am going to be driving it off the converter anyway, but wanted to hear it thru the tuner 1st.

.0051 no change. gonna just let it run for a few hours and see if it settles down (I know I should have done that in the 1st place, I have never had it on for more than a few minutes).

I did install a 175ma cathode fuse on the HOT. Its spec to run at 124ma which it does, so this is in case something goes wrong with the HOT, maybe it would blow and save my flyback.

Vertical sync has twice horiz frequency serrations, and sync separators are essentially low pass filters. In one field of video, the vert sync starts at a regular timed horiz sync pulse, the other field it starts at a halfway point between regular timed horiz sync pulses. The object is to try to avoid the horizontal sync from contaminating the vertical sync pulses and vertical oscillator circuits. If that happens, the interlace gets "line paired" and you lose vertical resolution. Scan lines on top of each other instead of halfway in between. But keeping the horizontal sync pulse out of everything else in the TV set is easier said than done, it gets into most everything. Maybe if the vert circuits use horiz B+ boost, a filter cap is not filtering well enough?

gonna try jumping in a cap on the various filter caps to see if that has any effect.

Vertical sync has twice horiz frequency serrations, and sync separators are essentially low pass filters. In one field of video, the vert sync starts at a regular timed horiz sync pulse, the other field it starts at a halfway point between regular timed horiz sync pulses. The object is to try to avoid the horizontal sync from contaminating the vertical sync pulses and vertical oscillator circuits. If that happens, the interlace gets "line paired" and you lose vertical resolution. Scan lines on top of each other instead of halfway in between. But keeping the horizontal sync pulse out of everything else in the TV set is easier said than done, it gets into most everything. Maybe if the vert circuits use horiz B+ boost, a filter cap is not filtering well enough?

after re-reading what you said, I am going to see if I can figure out the network that comprizes the low pass filter. I think I get it now (did some reading on trouble shooting with a o scope, esp vert sweep and sync circuits).

on what I belive was the low pass filter (a resistor cap to ground cap to grid of osc) from the sync separater/phase inverter I found a cap that was a .01 and per the schematic it was suppose to be a .002 (verified that on two other sets with the same chassis). It did not look original. I replaced it, still have the interlace instability (it jumps in and out). I put a scope on it and checked the input to the vert osc one check has it with the osc tube in and the other with it out (brt turned down). in both cases the wave seemed to move around on the scope, not so on the other set that is good. with the tube pulled you can see the sync pulse, on the good set it looks like the sams on the bad set the low part of the wave it thick, if I speed up the scan I can clearly see a hi freq wave in it. both sets have this, but on the bad set it in prob 4 times as big. I will post some pic later to try and make it clear what I am saying. the other scope readings of the sync sep and agc keying tubes were in conclusive, did not look anything like the sams, but neither did the working set. I will have to go back and take better notes, one ready I got was about a 3 order magnitude higher on the non working set than the working set.

checked it:
that was on the sync phase inverter grid, the non working set was much higher amplitude than the working set.

I would like to see a picture of the tvs picture with the interlace before you fix it.

I will snap one later. I may be making a moutain out of mole hill. I tried some OTA pics using a DTV converter (had been using a dvd), and it did not look too bad. I will take a pic of the good set vs the bad set for comparison.

Is this the macrovision lines you are seeing? Some sets are super sensitive to that where others aren't. Even the same general models seen to act different with the copyright crap on the dvds

something new (well not new just did not notice before i think) the scan lines at times seem to appear more as dots not lines. it Seems to be related to high contrast video. Considering the speed at which the scan line is being formed, what ever it happening must be at a very high freq. I am wondering if some how the video is getting clipped off? could it be an AGC thing?

oh will try agian on the pic, 1st try did not work out well.

I tried my dot/bar/line generator on it, no issues when using that, argh...

Cold I be in the IF stages or tuner? Also I have has issues with an RCA spotting waves of dots on the screen and it turned out to be an issue with the horiz afc tube. Even though it tested good I replaced it and problem solved.

I was advised to check the video at the diode detector, will give that a go.

I got this marker/genrator tool, big box with lights on what looks like a IF wave in the front. I have no idea how to use it, no manual etc... but looks like the thing you need to check/adj alignment.

the AFC for the horz on this one is a couple diodes, they were replaced a while ago, I figured the only function was to sync up the horz. I may try some tube swapping in the IF next from a known working set.

What bugs me is I was not able to get the effect on the dot/bar generator.

I think I may be looking for one of those B&K video analyzers, maybe helpful in chasing these dogs down.

I think I may be looking for one of those B&K video analyzers, maybe helpful in chasing these dogs down.

YES, Very useful. You can inject the signal at different stages and mostly isolate it down to one area. One of my best purchases so far.

Different sync signals are given between video feed and a generator. I have run into different sync pulses fed from a generator like by BK color/dot/bar generator than that of video feed from a VCR. Possibly some kind of overload?? Try turning down the AGC possibly.

I was thinking of checking the AGC voltages, no adj for it, but maybe a resistor has drifted. Something else, I was told it may be chorma crawl. I will have to google that...

giving the TV a break, pulled the TT (platter would not spin). the idler wheel had a big flat spot AND a nice divot (where the motor spindle must have been resting for years). The tone arm Ilder was still somewhat pliable, and I was able to work its slight divot out, but the platter ilder divot and flat were a whole nother matter. the rubber was rock hard. I chucked it up in the lathe and took off enough to get down to the bottom of the divot (the flat wa not as deep so it was gone by then). prob took just a bit less than 1/8 total off the diameter. I then found a suitable rubber band (from a broccoli plant) and placed it around the idler wheel. Its prob only at most 1/32" thick but nice tack to it. Tried it out, works great. I also found a MPX on epay so that will be here in a couple days. It's a nicer one (3 tuber) prob need a filter and a single coupling cap (it has a 1uf in there that goes bad). I will put it in and then take another look at the TV.

I am tempted to install a magnavox color TV (tubes of course) that I may be able get locally. the cabinet is shot so it would not be a sin to use it, except for the fact that this would then be a franken set.

another forum member suggested what I may be seeing is chroma crawl or dot crawl. Anybody here fight that with old B&W sets?

while messing about with it some more I noticed a horz linearity issue, the left side is wider than the right side, happens in the 1st couple inches. Odd thing is its larger while on another maggie with the same chassis I have a horz lineairity issue but its smaller, while on a 3rd its perfect. Oy...

Since there is no adjustment for horz lineairity, I will start by swapping the tubes from the good set to the bad (I dont think this will do anything, since I think I have done this already) the horz osc, HOT and damper. Next I will check the resistors and caps, again, pretty sure I have already done this.

Oh and the one that works has the worst looking flyback of all. reallly really bad, but works fine.

Crawl still there, not all the time but its there.

more fiddling, I had the width control set to much, backed it down and then readjusted the horz control pot and then the horz freq slug and now it looks like the horz lineairity is much better. So I will try the other set, but on that one I will try increasing the horz width since it had the reverse problem. Lot to learn working on these old sets.

Dumb mistake, I inserted the slug adj tool in the wrong slug (duh) when attempting to adj horz freq. It was one of the peaking coils I think. anyway it seems to effect the sharpness of the pic and the sound so I played with it and have it back to where I was (at least as best as I can tell).

Rookie mistake.

Dave, give us some pics to look at!!!

These dots you speak of... could they be interference from your source? I've had dots on the screen of old sets that turned out to be interference from DVD players. More recently, my daily watcher in the living room gets weird dots/lines in the picture when the coaxial cable from the satellite receiever takes a certain route behind the set. The sat receiver is a good distance from the TV set, however if the wire is in a certain area, it will throw some interference on the screen. It's not bad, but annoying. Reach back there and move the wire to another position and it goes away.

At first, I thought the wire itself was bad... tried another... same affect. I would not have suspected this at first being that the wire is shielded.

Although not as likely, but still a possibility is interference from something else in the home. My front porch light is on a dimmer. When the light is on (whether full blast or dimmed down), it causes lines on my TV and puts a loud buzz in AM radios. I can walk up to 200 feet away with an AM radio in hand before the buzz goes away. The lines going across the TV screen seem to travel up the screen for a while, then slow down and go the other way. Oddly enough, I don't notice them on my Diamond D, but they are very much there on a SS Curtis Mathes. All this trouble caused by a dimmer switch.

I will get some soon my camera is MIA right now (kids). Darn horz lineairity is acting up again, left side opens ups. I think I will try a tube swap ONE MORE TIME, then I will a carpet bombing replacement of every cap/res in the sweep board. I will try a diff yoke just to be sure.

here are some pics of the horz lineairity and interlace issues

if you look close you will see the left corner drooping down. On the cross hatch the vertical lines also sweep to the left at the top, about the 1st couple inches.

on the close up of carol you can see the courseness of the pic, due to the poor interlace. I can fiddle with the vert, minute adj will temp correct the interlace but it jumps right back after just a second.

The horz wave is from the input to the HOT, it has a little defect in the very begining, but I noticed that on another set that looks ok, so I do not think that is the issue. Since the shape looks good going into the HOT I have to assume its in the HOT/FLY that the problem exist. I tried a different yoke, same result.

The Horz lineairity is not a huge problem, cant even notice it unless I pull up a graphic with a lot of staight lines (like that program guide).

the interlace is a bigger problem. lastly is the dot crawl, I will attach a pic of that

Dot crawl

Does the dot crawl only stay at the very top? How far beyond the mask does the picture go? If you have the picture spread only to the edge, you're bound to find stuff there. The picture should go at least a half inch beyond the mask.

Are there any caps/resistors left in the verticle section that you haven't changed? Does this set use one of the combination components in the verticle section? If so, maybe you need to build a new one. I figure you've already done this, but I'll mention it anyway... cleaning the verticle pot with some spray?

response to Charlie


Does the dot crawl only stay at the very top?

Dot crawl is through out the pic

How far beyond the mask does the picture go?
its pretty close, have expanded it some, still have the issue


If you have the picture spread only to the edge, you're bound to find stuff there. The picture should go at least a half inch beyond the mask.

Are there any caps/resistors left in the verticle section that you haven't changed?

have checked all resistors, replaced any leaky caps (replaced 2 that were slightly leaky(, did NOT check the disk caps.

Does this set use one of the combination components in the verticle section?

yes it does I have comtemplated making one up, would not be hard to do. I have some scrap perfboard that would make it easy to do.


If so, maybe you need to build a new one. I figure you've already done this, but I'll mention it anyway... cleaning the verticle pot with some spray?

Can't recall for sure, will give it a shot to be sure.

Dave, that dot crawl lots A LOT like what my sets get when my front porch light is on (recall I mentioned having a dimmer switch on it) and mine goes through out the picture as well... the dots move horizontally across the screen, and the whole pattern moves verticle somewhat slowly. Not saying your front porch light is the problem (wouldn't that be freaky), but sounds like something external.

I would not suspect the disc caps, but that combo component would get one of those funny "raised eyebrow" looks that Mr Spock gives. :yes:

I will keep after it. :yes:

Did some more checks, this time on the AFC diode pack. the center (which is the feedback from the horz yoke, was right on spec for form and amplitude
(15v pp) however the sync pulse was off amplitude (both sides of the diodes from the horz intgrater) at only 5v PP correct form though...

I checked another set, same deal , center of horz AFC diode pack 15v PP other side of diode were both 5v pp but good form. the AFC lock seems fine so I will just chalk it up to an error in the sams (for now).

hmmm I did not think to check the contrast level, guess that could cause a lower video signal to be sent to the sync sep and therefore a lower sync pulse amplitude (if I am reading the schmatic right) I still have a LOT to learn.

I am also looking for noise on the vert sync pulse still that could be causing the interlace issue, will have to give that a go tomorrow.

It almost looks like tuner RF interference.. Check your 75ohm coax and make sure you have good grounds and no interference betwween that and any power cords or something in the line that would cause interference. Just a hunch. Back in the day when we had analog, I remember watching a VCR tape or playin Nintendo on my old CTC-38 and when it was set to channel 3, our KCRA channel 3 would bleed into like RF interference just like what I se in the pic. Color TV's seem to filter this as a crawl not so dot like.. B&W sets seemed to filter it in dots.. Nonethe less if I switched to channel 4, problem gone. And remember, you are supplying a very strong signal to the tuner.

well beed doing some more reading, going to try yet another Damper, also going to check the grounds of the vert hold pot. Read somewhere that if that ground get even sllightly bad issues pop up, esp with it sitting right next to the horz (this is for the bend it the pic on the left side).

played with the contrast no real effect on the amplitude of the sync pulse oh well so much for that. The only ohter thing in the path is that horz integrater. thats one I plan to rebuild just for grins. actually the odd thing was the sync pulse got a little stronger when the contract was turned down.

I may just break down and replace ever single cap and resistor on the sweep board. Not many really.

two new damper tubes were tried.. no change.

put on the cross hatch generator, hmmmm the horz lines look fine. the vertical get a little messed up at the top, but if I turn down the RF on the gen they get better. I dont get why the horz lines look fine from the gen but the horz lines on the OTA program guide bend down on the bottom left edge.

Put a indian head test pattern on it, not very good, this this is a pita to get looking right.

Back on the interlace/horz linearity (since my emerson idea got squashed today) I bought a bunch of caps, the plan is to pretty much redo the entire sweep board including some HV caps on the flyback/damper/HOT. there are a few 3kv and 5kv in there. I also ordered a bunch of 800 pf decoupler caps for the IF board, just in case something is going on there. The interlace issue is a bugger, more than anything else since it kills the resolution.

I would like to get this one done so I can move it into a bedroom and make room in the garage for another project TV. The current rule is I have to be able to put BOTH vehicals in (Explorer and Suburban) AND you must be able to get in them with out having to pull one out 1st.

I still want to get a Maggie astro roundie color up in TN, that is a biggie.

ok back to this one.

Pulled the chassis, while I had it out I decided to clean the tuner, I noticed the gear the turns the little tuning slugs was stripped. I had a junked tuner so I was able to replace that gear. Cleaned the turret buttons with an eraser and them lubed them back up with some tuner cleaner/lube.

I am going to replace some more caps on the deflection board and on the damper tube. I scoped the grid of the vert osc last night and it def has a lot of Horz noise getting in there (when compared to the other set with the same chassis). Not sure exactly how its getting in, lead dress looks good. I am hoping by replacing the remaining caps I will just get lucky. Its just too darn hard pulling this chassis and PCB work is easy so I figured might as well. there are not a lot of cap anyway. I dont like the way the vert hold pot ground is shared with the horz hold pot but it works on the other set...

Anyway will get back on it tonight.

Im sure you have checked but if there are any of those little domino caps with the dots, replace them. These caps have driven me nuts causing all kinds of sweep issues.

Stick with it Dave:banana:

too new for those, only have polys and disk (there were a few papers HV ceramic tubes but they got replaced on the 1st go round but for one that tested good and I did not have the right value, needless to say its going tonight).

I am kinda stubborn so I will be sticking with it. :)

I also found that it seems like the stereo tuner has been wired to only have a L and R on the phono, I bought a MPX subchassis planning to make the FM stereo switch posistion functionally, but I will be darned if it does not take the two input jack and mix them before going to the preamp tube.

I may need ot swap out the switch, its not the conventional two piece waffer. I ran into this early when trying to use it for stereo TV audio, but I did not think it was wired to mess up the FM stereo also (esp since it has a switch pos "fm stereo").

Gonna take some more reviewing of that.

oy vey is mir, this thing was an exceedrin headache number 25....


I "think" I have it licked. Excessive horz freq feedback thru the vert out tranny do to yoke. I swapped out the yoke and my sync pulse at the grid of the vert osc tube looks MUCH better. I am too tired to hook it all back up for a visual confirmation that the interlace is good, but at least my wave forms are looking better.

Could not wait, perfect interlace :banana:

will button up the TV part tomorrow and take another look at the MPX for the tuner.

figured my problem on the MPX hookup I just had it plugged in wrong, BUT the mpx is not working as there is no channel separation coming out of the MPX. I have worked on these subchassis before so I dont expect there to be too much wrong. I just need to get it on the bench. guess is a decoupling cap that is open. plus there is at least on big paper cap in there IIRC that causes problems.

On the TV single input to stereo mod (will use the DVD/conv box for L and R) I found out how the switch is hooked up. It has one waffer that is NO for all but the TV, there is shorts, and it connect the two center taps of the audio together. I should be able to put in another RCA jack, and use that shorting position to connect the RCA to the high side of the pot that was originally being shorted to the other channel that the TV rca was hooked to.

then I will have L and R RCA's when in the TV position. To use the TV chassis for audio sourc a L+R adapter will be used, or just use the stereo feed off the signal source device for true stereo. Looking good but need to get the MPX going 1st.

Got the MPX going, needed a couple caps and a tweaking of the coils to get the separation working right. Those coils are very critical, must use a scope to see what is going on, 1/8 turn makes or breaks it.

Only thing left is the turner/preamp mod for stereo TV audio input.

Whew getting close now...

The yoke was the problem? Is there some kind of leakage between the coils or?

Not that I could detect, but it sure made a big diff, not only in the interlace but also just the mechancial sound, it was less harsh (the 60hrz buzz). I plan to try the bad yoke on some other C36 maggie chassis I have to see if the problem follows the yoke.

Maybe there is one shorted turn. Also there are often resistors and or caps inside the back of the yoke.
Did you have a bk 1077? The yoke/flyback test works fairly well and would most likely show a shorted turn.

no 1077, been looking on ebay for one or a 1076 (I wanted an all tube version), just looking for a clean one.

Looks like I may have to yell uncle on the TV stereo mod. the switch wafer not only short on the TV postion but on AM/FM/FM afc as well (should have realized this since its the only way to use a mono signal on each channel).

I guess I could rig it so the TV has an independent power switch. I could then use the stereo in AUX mode for sound and turn on the TV with the separate switch.

Could you do it with a relay or couple of relays?

I was just thinking along those lines. I just need to break the connection when the TV is on, which would not be a hard thing to do. Could go with a NC setting power off and leave the pots shorted for mono, then when power on to the TV (which is controled by the stereo tuner) it could energize the relay, breaking the connection.

Maybe something worth looking into. I have some plug in 120vac relays.