heres my newest project

another front photo

I am helping out a friend trying to get this up and running . Its a model 22BU4302. Have not found a chassis number yet . It has a 21zp4a picture tube . Here is the tube layout in this set .

12b4a (vertical output)
12au7 (vertical osc)
6al5 (phase comp)
12au7 (horz osc)
6bq6gt (horz output)
1b3gt (hv rectifier)
6ax4 (damper)
6cb6 (if amp)
6x8 (osc mix )
6bz7 ((rf amp)
6au6 (video amp)
6v6gt (aud)
6t8 (agc/fm det)
6cs6 (sync sep)
6aq5

I am trying to obtain a schematic however have not found one yet . Found the horizontal output tube bad , replaced that as well as the damper and rectifier . Powered it up breifly on my variac and had high voltage and sound , however i had just a white horizontal line across the screen . Then replaced the electrolytics ,wax caps and bumble bee caps . I used orange drops there . I only worked on the chassis on right side which is the vertical, horizontal and high voltage . Put the chassis back in and got the same issue . Checked the pots(vertical height and lin, which were definitly dirty, sprayed them with some de-oxit and then they seemed to read ok in circuit . Still have same issue except the horizontal line opens up a but more when height is set to max . Seems to be a straight forward set, however my next step is obtaining a shematic and i guess check all resisters , then go from there . Can anyone chime in and give me any advice .

thanks
Mike

Sorry I can't help but just wanted to say that's a very nice-looking Philco.

Reece

I've got a 22BU4001, a cheaper tabletop version that was my dads in college. It was my first attempt at a electronic restoration. This was around 96-97 when I was in 8th grade. I recapped the set, but after it had a sync problem. Wouldn't lock vertical or horizontal. I was told to check the sync resistors. That was too hard then, having to disconnect one side just to test it accuratly. I moved and the TV has been in storage for 10 years. It is 3000 miles away and still awaiting those resistors.

I'm sorry my schematic for the TV is with the set. Why don't you order one from Justradios.com? Its always great to have a schematic on hand.

My dad hated the TV. It was great when it worked, but it uses a hot chassis design, and there are two metal CRT support brackets that extend to the top corners. The focus adjustment too is connected to ground and is "hot" too. He got shocked by it in the 60's and put it into storage in our basement.

So be careful after you have the TV back together and have to adjust something. be sure your not grounded!

Best regards,
Matt Davala

i dont think mine is a hot chassis . I am obtaining a schematic shortly so i can see what i am up against here . The high voltage chassis is almost completly recapped. I didnt check the red mica caps yet becuase i was under the assumption they usually hold up till i talked with a friend who advised me to check them becuase of their age . I am assuming i can check them with my sencore LC103 i hope or a meter . I guess if there are bad ones in there then i will order new ones from antique electronic supply. I dont know who else might have them , maybe Moyers . I was wondering am maybe someone can chime in if the red mica caps could be changed with regular mylar caps . I seriously dont think so but i wanted someone elses opinion . I also found two bakalite caps or at least thats what they look to be stamped 400@.047 , i am assuming regular orange drop replacements should be ok . Next week the schematic should be here .

I have a good shot at having the Sams. I've been organizing them over the last week; I'll try to check tonight.

That is a "hot" chassis. One side is connected to the AC. For shock protection and safety, use an isolation transformer. If you don't have one, make sure the set is connected with the chassis on AC neutral. Measure from chassis to power line ground and look for zero AC voltage. If you measure 120 VAC, reverse the plug.

That is a "hot" chassis. One side is connected to the AC.

A brief look at the tube line up made it look like a transformer powered set, and I thought I saw a power transformer in there. But I don't see a rectifier tube in the list. Must be only a "filament" (heater) transformer and otherwise a hot chassis. Probably a selenium rectifier (maybe a doubler circuit) in there. I've seen sets that have the chassis at voltage either way the plug is plugged in, chassis tied to a negative rectifier output, and B+ tied to a positive output of a 2nd rectifier. Similar to how a modern PC power supply, set to 120V mode, does it on its input (line) side. And modern SS sets usually have a bridge rectifier, so the chassis ground looks to always have about 80VAC on it. Isolation transformers would be a must. One that can do around 250W should be what you'd need.

Mike, I do have the Sams. Send me a PM with your address if you want it, $3 be alright?

i did obtain a sams from Moyers , i did arrive yesterday . Yes you guys are right it is a HOT chassis , i havent done one of these yet so i didnt reconize it right away

HHm , well i will take Don Lindslys advice and check the ground at the plug before operating . It does have two selenium rectifiers and from what i seen last night they are a doubler circuit . It would explain the way i saw the one electrolytic ground wiried and the wiring of the rectifier . I did power up before with a cheater cord before i actually read this thread and realized what i was dealing with . It powered up fine , i think it works either way however i hope i didnt damage anything . I pretty much has high voltage and sound however it has a vertical issue . I have a horizontal line across the screen . I have yet to recap the IF/TUNER/VIDEO chassis yet , maybe the problem lies there . I do not have a isolation transformer and would like to obtain one soon but i have not come across one and i am afraid of buying one on ebay and it wind up being someones broken junk . I have had bad luck with buying test equipment from Ebay . It usually does not work and gets damaged in shipping . Usually my best bet is a radio swap meet or a yard sale .

The problem described is in the vertical sweep circuit, not video, IF or tuner. I would suggest changing only the molded caps on the RF chassis, not the ceramics now. The RF plate limiting resistor is the most frequent tuner trouble. It will not cause your symptoms.

Make sure all the voltages are correct in the vertical circuit. Height, hold and lin controls are a place to start and, of course, the two tubes. Check coupling cap from vertical oscillator to output and discharge cap from vertical oscillator plate.

Thanks Don , i will check that tonight . I also found today a new isolation transformer from a parts place i been using and got a great deal on it . So i took the plunge and bought one . A little more then i want to pay for it however its definitly something important to have on the bench when working on old tvs and radios . It is suppose to be able to handle up to 450W , WHICH IS A BIT OF A OVERKILL !!!! But better then not being up to what i need . The two tubes vertical ossc and output are new . There is a bakalite .047 @ 400 cap which is in the vertical circuit that i have not replaced yet .

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Make sure you only change split chassis halves with one of the same number. They are marked with numbers like RF91, RF44, etc. The other side will be marked with D191 type numbers. Don't mix and match. Each RF chassis is intended to go with a specific deflection chassis. Plugs may fit, but the wiring varies.

Good move on the isolation transformer. That is the safest solution.

I have a 53 Philco with the same type chassis.

If you see any flat square capacitors that look like Mica or say Micamold on them you should change them.

This little cap here shorted solid enough to blow the fuse.
http://www.audiokarma.org/forums/attachment.php?attachmentid=123060&stc=1&d=1229205871

Don is right about the chassis numbers also, make sure your schematic is for the numbers you have.
I struggled with one set for years after recapping because I had the wrong schematic!

I understand that Micamold made paper capacitors that looked like mica and that they caused many problems.

When you say "any flat square capacitors that look like mica..." do you mean to replace them also because they might not be mica?

John

I found three caps that looked like mica or bakalite. Two were 400@.047 and one at 400@.022 . They were original and stamped . Replaced all three . Now i have 3/4 of a screen , which is a improvement however not there yet . I can fill 3/4 of three screen with height control at its max .I checked all resisters in this set and they seem ok or within range of what they are suppose to be . Only found one way off which i replaced. There are a couple of mica caps which have not been replaced yet , however they dont appear to be in the directly in the vertical circuit . I sprayed the controls with de-oxit and also gave the tube sockets a quick spray . Even wiggling the tubes in the socket makes no difference, so i guess i can rule out bad connections . Guess i will continue my trouble shooting tonight . Got my isolation transformer in yesterday . Got a question . Can i pull the high voltage sweep chasiss and being the a/c plug does plug into it , can i take voltages on the bench with just that chassis or do i have to pull the other chassis and have the yoke connected . The schematic i have seems to be correct so far .

You need both chassis and the yoke for all the voltages to make sense. It's not much trouble and you can be fooled by the missing half. I would not recommend running the sweep chassis without the yoke. That will throw the boost voltage off as well.

Check the resistance of the height and lin controls and the resistors in series. Check for a high resistance from the height control tabs to ground. That should read open. Sometimes grit will get in the front of the control and load down the voltages slightly.

The discharge cap off the oscillator plate is another suspect.

What is the chassis number?

A bad pot can play tricks on you. I've pulled my hair out only to discover the trace inside one was cracked.

Make sure you got rid of every black beauty since they all will be bad.

Thanks guys for all your help . I am going to recheck the vertical height and lin controls again . I believe two mica caps are bad in this set . It has a total of four in this chassis . Will be removing them tonight going to check them . I never had to replace a mica cap yet on anything i worked on . I usually thought they were pretty reliable however i guess after 50 yrs anything is prone to fail . My next step i guess after that is the voltage readings .

I have a '53 model thats nearly identical to that. Mine has a different grille cloth and some brass stuff in the grille, but thats about the only obvious difference. Also mine doesn't have the paper tube up to the deflection coils.

Mine had 2 bad silver mica caps in the horizontal stage, causing the oscillator to be extremely unstable. SM caps are generally reliable but after 55 years anything is possible. It was also packed with black beauties, most of which were split open. I still need to do some more tweaking, the picture is a bit cone-head looking but I think thats just adjustment at this point. I haven't had time to mess with it though. If you play with the adjustments, you'll find the vertical linearity and the height control interact, so if you can verify all the parts are good, it might be a case of adjusting both controls to get a full size picture.

Also, the model number you should be able to find on a paper stuck behind the speaker somewhere. Mine was on the left side as viewed from the back. It should be two numbers, a dash, a T, then a model number. The first two digits are the model year.

Hmm, maybe you can replace the "black beauties" and come out ahead financially. I guess audiophiles don't mind the risk.:guitar:

http://www.tmworld.com/article/CA439412.html

John Y.

The black beauties in the high voltage sweep chassis were all replaced already with orange drops . I am doing this set for a friend . He replaced a few caps before bringing to my house . I did find last night that there are suppose to be 2 120mf electrlytic caps in the power supply / rectifiere stage . One was replaced with a 100mf, so i am going to correct it and add another cap(22mf) to make it the correct capacitence . Also found a off value resister in the supply circuit as well . I aint sure if this is my problem however it needs to be addresssed i gues before i start taking voltage readings . One of the mica caps in the horizontal circuit tested shorted when i checked it with my DMM , however i tested it in circuit . Does anyone know if i can plug in this chassis alone on the bench to check if my supply voltages are correct ????

Well i finally fixed the vertical issue, it was a wrong value cap that i installed . I read the bumble bee cap however the schematic listed a different value . After reinstalling the cap according to the schematic the vertical height came back . My friend who owns this philco came over and recapped the if/rf chassis and now we lost sound . Back to trouble shooting . Does anyone have the philco logo which goes inbetween the front controls .

Thanks Don , i will check that tonight . I also found today a new isolation transformer from a parts place i been using and got a great deal on it . So i took the plunge and bought one . A little more then i want to pay for it however its definitly something important to have on the bench when working on old tvs and radios . It is suppose to be able to handle up to 450W , WHICH IS A BIT OF A OVERKILL !!!! But better then not being up to what i need . The two tubes vertical ossc and output are new . There is a bakalite .047 @ 400 cap which is in the vertical circuit that i have not replaced yet .

Good for you! :thmbsp: That isoformer is worth every penny you spent! It's too easy to "forget" and plug the set in the wrong way. And some old radios back in the day had the on-off switch on the chassis side of the line, meaning with the plug inserted one way you get a 60~ handshake when the radio is off, the other way and it'll give you a zingie when it is on. It's not only your own life at stake but remember that your generators, bridges and other 110V operated test gear can get caught in the loop as well, and suffer damage.

Well with the help of a few AK members this set is up and running . It went home to its owner a friend of mine this past weekend . IT performs excellent and was running in my basement for hours. After fixing the vertical issue , then my sound was lost when i recapped the IF/RF chassis . It wound up being a loose connection . Then i had a no video problem, justy a grey screen . With the help of a fellow ak member it turned out to be a bad contrast control .

thanks guys

Well with the help of a few AK members this set is up and running . It went home to its owner a friend of mine this past weekend . IT performs excellent and was running in my basement for hours. After fixing the vertical issue , then my sound was lost when i recapped the IF/RF chassis . It wound up being a loose connection . Then i had a no video problem, justy a grey screen . With the help of a fellow ak member it turned out to be a bad contrast control .

thanks guys

Hi Mike;
Glad to hear you finally conquered the beast.

Seems like it was a long hard fought battle, but once again persistance and patience have paid off.

Each set we work on is a new learning experience, and it's great to have a place like AK where knowledge is plentiful and people are always willing to share it.

Congratulations and keep up the good work!

Bob