Howdy all,

I just joined Videokarma and was looking for some info on this analyzer. I'm mid-stream in rebuilding/restoring it and was wondering if there is any way to date this (approximately)? It is SN=8351. I've read on the net that this model was produced ~~ 1936 through 1945?? This one has the smaller 2mm pin type test jacks and from other pictures, I've seen it looks like later models used the more standard 4mm bananna type?? Also, the tube sockets use nuts & screws where (I guess) later versions were riveted in? I think Bob Andersen's unit had this type as well as a factory 6X5 type rectifier? Mine is the 4 pin type-IV tube. Waiting for some 1% film caps from Mouser (back-ordered till the end of this month :sigh:.

Any help appreciated.

Tom D.

Hello Powerking!

I just acquired one of these awesome units myself, (Serial 5941) and I'm now hoping it arrives mostly intact. I've found the manual and schematic over on 'bama but it doesn't include a parts list or values. Could you point me to a link that has these, or share what yours has? I'm going to try to get the parts ordered so they arrive before or shortly after the unit itself and I'm not stuck in the same boat you were at the time of your post.

Can someone also possibly confirm that "type IV" was later changed to "1V" (both are 4 pin low drop rectifiers.) in case I have to source some working bottles? (I have 3 compatible eye-tubes, but the rectifier has me scratching my head a bit here.)

I think the banana jacks are just a common retrofit that owners made over the years. I think we've all owned at least one piece of test equip with a lead snapped off in the pin-jack.


Thanks in advance!

--Nopegs

I think the IV/1V are the same tube, just which character you interpret it as "I" or "1". Later versions of the tester went with an 80 type then the 6X5 rectifier from what I can tell. See the attached files for the parts list and schematics. Good luck with your restoration as well.

Tom (PK):thmbsp:

Although mine is wired for a 6X5, the panel says "IV".

Interesting is that a Solar Analyzer is up for bids on the auction site. It has the classic note that the power transformer smokes when it was plugged in.

Sound familiar? It is a shame that stuff gets destroyed! Some of us just don't know...

kvlfyer;

Ah, my old stomping grounds in Catonsville, MD... Lived there for 25 years while working for HP. What a nightmare the traffic was getting around the beltways when I left for NH in 2003. I'm sure the Springfield VA "mixing bowl" is now nothing more than total KAOS since I left. Yeah, this guy trying to sell that CA model analyzer is out of his mind (IMHO) and has been listing it for many, many months; no price change. Without a good power transformer, any vintage cap tester is pretty much worthless.

Tom (PK)

Hello Powerking!

I just acquired one of these awesome units myself, (Serial 5941) and I'm now hoping it arrives mostly intact. I've found the manual and schematic over on 'bama but it doesn't include a parts list or values. Could you point me to a link that has these, or share what yours has? I'm going to try to get the parts ordered so they arrive before or shortly after the unit itself and I'm not stuck in the same boat you were at the time of your post.

Can someone also possibly confirm that "type IV" was later changed to "1V" (both are 4 pin low drop rectifiers.) in case I have to source some working bottles? (I have 3 compatible eye-tubes, but the rectifier has me scratching my head a bit here.)

I think the banana jacks are just a common retrofit that owners made over the years. I think we've all owned at least one piece of test equip with a lead snapped off in the pin-jack.


Thanks in advance!

--Nopegs

If it was mine, I'd change the jacks to the banana type.
The 1-V tube is available at ESRC for $5.00. Not all that common of a tube!
It has a 300ma heater, where the 6X5 tube, has a 600ma heater
I have an older Detrola radio, that originally had a 1-V rectifier. The socket was changed to use a 84/6Z4. :boring:

kvlfyer;

Ah, my old stomping grounds in Catonsville, MD... Lived there for 25 years while working for HP. What a nightmare the traffic was getting around the beltways when I left for NH in 2003. I'm sure the Springfield VA "mixing bowl" is now nothing more than total KAOS since I left. Yeah, this guy trying to sell that CA model analyzer is out of his mind (IMHO) and has been listing it for many, many months; no price change. Without a good power transformer, any vintage cap tester is pretty much worthless.

Tom (PK)

Hi Tom. Yes, the traffic here is still a nightmare. My name is Don Cavey. I went through the Mixing Bowl a few weeks ago. Driving up from my new home in Fernandina Beach, FL. Traffic was just fine... until the Mixing Bowl. Then the usual that you remember, stop and go. I can't wait to get back to Florida for good.

Anyway, back to the Solar. I don't have one but eventually (when I finish moving) would like to add one to the collection. In addition to my junk around here, I like vintage test equipment. Several of us were criticized one day for fixing "useless/inaccurate" old test equipment. What I mentioned was that yes, we know that a modern Fluke meter is more accurate. Hmmm, maybe collecting and restoring vintage test equipment is ALSO a hobby!

So, back to the subject line, hope it gets fixed and is brought back into use.

I think the IV/1V are the same tube, just which character you interpret it as "I" or "1". Later versions of the tester went with an 80 type then the 6X5 rectifier from what I can tell. See the attached files for the parts list and schematics. Good luck with your restoration as well.

Tom (PK):thmbsp:

Excellent! The parts list is exactly what I needed. I'm presuming that 600v poly caps and 450v electrolytics are enough. Although, if the leakage test goes up to nearly 500v I could be wrong on the electrolytics, so this is me seeking your advice before I give mouser my order. C6 is right across the rectifier and C7 sees about 1/3 of the same voltage through the divider, too...

R4 is the main current limiter, for shorted or terribly leaky caps, correct? Any thoughts on putting a 100ma fuse in line with the rectifier to protect the HV secondary winding in case of terrible things?

Thanks for clarifying my thoughts on the rectifier. Hopefully I won't need to source a replacement, but if I do now I know where I can get an actual I-V instead of adding a 600ma filament transformer and changing the socket or rebasing a 6X5 to fit.

Hey, thanks for posting this. I have one without a case- anybody have one?- and in shambles. This helps with values on components.

Yes the correct designation is 1-v, pronounced one vee. Of course a silicon diode will work, with the associated resistor.

Hey, thanks for posting this. I have one without a case- anybody have one?- and in shambles. This helps with values on components.

It's just a wooden box with some fancy two-piece hinges, a latch, and a handle. I don't think I could spend more than about $50 building one out of something exotic like genuine solid hardwood and vintage hardware from the internet.


You're in the best possible situation to have the internals but no box, versus somebody out there who probably has the box and most of the internals save one unobtainable part...


If you're still looking for boxes once mine arrives, I'll take a look at the construction and consult with my better half as to what wood it's made of and how hard it is to duplicate it, but I bet I could ship you the pieces IKEA style and you'd just have to lash it up with some wood-glue and screws. Eyeballing photos I'm sure we could make one out of plain old pine for a few bucks, or something less "pauper's coffin" for $25-40 or so.

Yes, the girlfriend does most of the woodworking in the relationship. It seems to work just fine that way... :banana:

Here's a photo of mine. Simple, but does have some nice finger joints. I'm not sure of the species - oak ? maple ?
https://farm8.staticflickr.com/7414/14136177472_d7396351b9_z.jpg (https://flic.kr/p/nxaB4N)

Below are a few more Pic's of the box/cabinet (what it originally looked like). I also have to cut a piece of leather for the replacement carry strap.

Tom (PK)

Yes the correct designation is 1-v, pronounced one vee. Of course a silicon diode will work, with the associated resistor.

Yes, but where's the joy in that while 1V and equivalents are still around? If it wasn't a huge part of the visual presentation of the front panel, sure. Even if I did just bung a tube with a good heater in the socket for looks it'd still keep me awake at night just knowing...


Here's a photo of mine. Simple, but does have some nice finger joints. I'm not sure of the species - oak ? maple ?


Oh dear. If you can't identify the species, what hope do the rest of us with significantly less hands-on experience have? :D I might have to consult one of the local Amish artisans for a professional opinion then. (I was thinking ash or poplar. Pretty sure it isn't maple.(Edit: I'm bad at wood identification.))

It is finished with shellac, right? Or is it something like tung oil?

Below are a few more Pic's of the box/cabinet (what it originally looked like). I also have to cut a piece of leather for the replacement carry strap.


Looking at everyone's pictures it almost appears that they built the 4 sides of the box and then ran the whole assembly through a bandsaw to divide the main body from the lid portion. Grain lines up and everything. They sure don't put that kind of effort into modern mass produced wood things.


I also noted that a replacement cabinet was available for $3.50! At $15.07 piece-meal replacement cost for everything to make one unit, the cabinet alone makes up almost 24% of the BOM total!


I know some of you collect vintage printed media, anybody have a catalog page or other advertisement for these things? They probably list the type of wood used in the cabinet along with the other features and functions. I'd also be curious to know what the original selling price was, I'm figuring probably $19-$24 because you sourced your own tubes according to the manual.


Mine is currently in the hands of the USPS. Kansas to Pennsylvania so I'm hoping they don't have too much time to damage it. Only time will tell.


I'll also bring your attention to the fact that there's a bunch of new manufacture very reasonably priced NE-48 (B9A) glass and metal neon bulbs for these (and so much other vintage gear) up for sale on the auction site. I finally managed to find Bob's original post about his CB-1-60 and he mentioned that glass bulbs were pricey at the time, but a very cheap and nasty looking plastic functional equivalent was available. Not sure if anyone has brought it up recently or not. I'm still telling myself that I'm not going to get a beat up box full of broken glass and wood next week, but I'm exploring all of my possible contingencies should that come to pass. I wouldn't be worried except for the fact that the seller expressly mentioned "for steampunk" in the main description. That's always a sign of a fully qualified package-smith, you can bank on that! :tears:

At least they didn't plug it in.


One last question in this morning's rambling post:

R7, 8, 9, 10, 11. One unit construction? That's the tapped Canned-Ohm bit, correct? Is it 36kOhms end to end, 5 sections at 36kOhm each, or something way less intuitive with each section being some randomly determined secret value adding up to 36kOhms end to end? :scratch2: I'm vaguely familiar with a wein bridge, but I'm not 100% sure that the divider is only used for the leakage test and doesn't interact with the bridge for value determination. What I'm asking is should this be on my list of things to go precision tolerance on for best overall accuracy, or is it just controlling the leakage test values and could be replaced with 5% 1w units if mine is missing the magic smoke?

Final rambling thought: I love how resistor prices have more or less remained the same for single quantity mail-order type purchases despite inflation in the last 70 years.


Thank you all again for your advice and opinions! They are much appreciated.

--NoPegs

Informational update. I consulted another matriarch of things woodworking and until I can get her some images of the unfinished interiors and/or endgrain structure her best guess is something along the lines of Norway Maple...

http://www.wood-database.com/lumber-identification/hardwoods/norway-maple/

Goes to show that being from the northeast most of the maple I see doesn't look anything at all like that when sawn...

My brain thinks of this as "maple"

http://www.wood-database.com/lumber-identification/hardwoods/hard-maple/

Regarding the Canned-ohm resistor network, I replaced mine with 5 7.5-Kohm 5% 3w metal oxide resistors arranged on a terminal strip w/teflon tubing on the leads. This is 50% more power rating than the origninal (~~ 7.5W dissapation on the Canned-ohm network). Math of 500V accross the network comes out to about 7.5W. From the schematic, to me that is all this piece of the circuit is used for; the capacitor leakage test voltage accross the cap being tested; nothing else. When I measured each of the sections of the Canned-ohm one, they were not exactly "close" to each other; hence why I replaced it per the above.


Tom (PK)

Looks to me that the resistor network also supplies the plate bias for the eye-tube.

Yup, I mis-spoke about the leakage resistor network. It does supply the ~~ 200Vdc to the 6E5 tube (tap off the position #2 of the leakage/selector switch and where the other 8uF cap filters it too)..; my bad...

Tom (PK)

Regarding the Canned-ohm resistor network, I replaced mine with 5 7.5-Kohm 5% 3w metal oxide resistors arranged on a terminal strip w/teflon tubing on the leads. This is 50% more power rating than the origninal (~~ 7.5W dissapation on the Canned-ohm network). Math of 500V accross the network comes out to about 7.5W. From the schematic, to me that is all this piece of the circuit is used for; the capacitor leakage test voltage accross the cap being tested; nothing else. When I measured each of the sections of the Canned-ohm one, they were not exactly "close" to each other; hence why I replaced it per the above.


Tom (PK)

Looks to me that the resistor network also supplies the plate bias for the eye-tube.

Hmm, I'll play it by ear when it arrives. I know eye tubes can be finnicky, but usually its the 1meg between the plates that screws them up. I'm hoping my can of ohms hasn't leaked and this is all just undue worrying on my part. :D

Yup, I mis-spoke about the leakage resistor network. It does supply the ~~ 200Vdc to the 6E5 tube (tap off the position #2 of the leakage/selector switch and where the other 8uF cap filters it too)..; my bad...

Tom (PK)

Edit: Disregard this. I have brought shame upon my house by screwing up Ohm's Law in public.

I think your math is a bit off there, 500v into ~36k is, indeed, just under 7W on a good day, however if you replaced them with 3w metal film resistors, you're in for a potential smoke scenario, because they're in series. Still only rated for 3W. :smoke:

(I bet you mistyped it, or maybe your rectifier is just that far gone that it can't stump up the full 14mA for some reason.)


In related news my CB-1 is now within 50 miles of my door. Will it get here today? I hope so. Will it make very sad noises when I pick it up? I really hope not.

NoPegs,

My math should be correct. The original Canned-Ohm resistor sees a TOTAL power dissapation of ~~ 7.5W. Therefore if you put 5 7.5K-ohm 3W resistors in series they are each dissapating about 1.3W @500V end-to-end. And I used metal oxide 5% ones, not metal film (not that critical for the leakage tests).


Tom (PK)

NoPegs,

My math should be correct. The original Canned-Ohm resistor sees a TOTAL power dissapation of ~~ 7.5W. Therefore if you put 5 7.5K-ohm 3W resistors in series they are each dissapating about 1.3W @500V end-to-end. And I used metal oxide 5% ones, not metal film (not that critical for the leakage tests).


Tom (PK)

Argh! You're right. "100v each" at 13.4mA is 1.34W... Next thing I know I'll screw up my zip-code!

At least if I screwed this up in the past my error was on the safe side of the equation instead of coming up short(ed). :tears:

Allrighty! I was surprised to find that the seller did an excellent job of packing it. I had asked to put something firm but squishy between the lid and the dial plate, because in the pictures he listed with it, there were no screws holding the face on. Strangely it arrived with 9 out of 10 screws installed, and the 10th one was discovered inside the cabinet.

I did some quick poking after unboxing it yesterday (Working 3rd shift is a bummer, didn't get delivered until almost 1400, I stayed up for it.) just to get a feel for it. I think the segment of my candohm furthest from the chassis connection is open, but I only grabbed the DMM out of my go-bag to check, and the probes it has are kind of dull and awkward so I'll be double checking that in the next day or so.

The good news seems to be that all windings on the power transformer have what appear to be valid readings of resistance. The main potentiometer also checks out in both overall value and linearity. Bonus points awarded because the mechanical action is nice and smooth too.

My "goat" shields are unpainted and kind of corroded, so I have to figure out how best to polish them up without flattening them out in the process.

There is rust inside, but not anything serious. Going to get a new pot of naval jelly if it doesn't come right off with some steel wool and cutting oil.

I'll see about taking some decently composed pictures, but that might not happen till the weekend.

My initial thoughts are "Well, it turns out to be smaller than my breadbox." I knew they were smaller in person, but when I sent the better half a quick cell pic of it next to my previously mentioned breadbox for scale, she commented on how "cute, but intelligently cute." it is. I quite like it myself, but its good that she approves. :D


Were the front plates lacquered/shellaced/varnished? Mine has a strong brown tint to it. I prodded it with some denatured alcohol and it comes off, nice and shiny underneath. I honestly can't tell if it's aged shellac or decades of tobacco smoke tar. I just gave it another eyeballing and the inside of the lid has some "condensate" on it. This could be from being stored in a hot attic for years with the lid closed. Baked the shellac off the wood. Might have solved that mystery myself just now.

After stripping the goats off the tubes, it looks like at some point in the past someone "cleaned" the tubes. Neither have markings that I can reveal with any of the usual voodoo. (I haven't tried gold sputtering, although I do have a stash of gold leaf on hand, *mad science cackle*) Obviously the eye-tube is an eye tube. The rectifier is a UX-4 base so probably a 1V, but I can't be certain due to the absence of markings. It's a Sylvania with the really, really old logo. Definitely a rectifier from the internal construction.

I'll admit to only having an emissions type tester, Accurate Instruments Co 257. No UX-4 or UX-6 sockets, and I know I can't make the eye tube do anything with the voltages it supplies, but if I break out the pins and connect the 1V up, 6.3v filament, and test it like one side of a 5U4 or 6X5 (Which I can test with my unit.) I can confirm that it hasn't failed, without blowing it up in the process, right? (After my epic failure at Ohm's law yesterday, I'm kind of spooked now.)

Filaments are good on both tubes, hoping I lucked into a low-hours eye-tube in the process, but I won't know that for a while.

I'll ask the wood ladies what their final answers are, after I take some better lit pictures. The good news is whatever wood it is constructed out of, replicating it will be a trivial task, so you need not remain sans-cabinet much longer, drdave3!

I may end up just lightly steaming mine so it deconstructs, trace out the panels and then glue it up nice and solidly again. It's just a wee bit loose as it sits. I have to think about that.

Has anyone tried to calibrate one of these things? I mean just improving the overall accuracy, not anything excessive like you'd do for a scope or VTVM... Seems to be a calibration pot inside, and the manual mentions factory re-calibration. I'll take any tips I can before pushing into new territory and experimenting myself.


Wow, apologies to anyone who's still reading after the wall of text up there. Thank you!

The hardware and hinges were nickle plated steel. I cleaned mine up using the ultra-sonic cleaner with Birchwood-Casey case cleaner solution. Then used the Dremel tool with a felt buff w/jeweler's rouge. Then totally clean them with acetone and paint with clear lacquor. I had researched some "home" nickel plating products but decided this was too much money for the desired end results. I'll post pictures of the final "product" forthcoming.

Tom (PK)

The hardware and hinges were nickle plated steel. I cleaned mine up using the ultra-sonic cleaner with Birchwood-Casey case cleaner solution. Then used the Dremel tool with a felt buff w/jeweler's rouge. Then totally clean them with acetone and paint with clear lacquor. I had researched some "home" nickel plating products but decided this was too much money for the desired end results. I'll post pictures of the final "product" forthcoming.

Tom (PK)

Ask your local gunsmiths if they could get them plated for you with their next batch of bits they send out... I bet you're pleasantly surprised with both the results, and the "cost" of tagging along...

I'm looking at mine now and I never would have thought "Hmm, this was nickel plated." Makes sense now that you point it out, though.

Might want to watch the filament voltage when you test the 1V. Some testers depend on the filament current to load the filament supply to the right voltage. I don't know the filament current specks of the 1V so this might be an unimportant point.

Might want to watch the filament voltage when you test the 1V. Some testers depend on the filament current to load the filament supply to the right voltage. I don't know the filament current specks of the 1V so this might be an unimportant point.

You raise a valid point. Sadly in my case my unit is just a tapped autotransformer, I have 1.4, 3.0, 5.0, 6.3, 12.6, 25, 50, and 115v filament voltage positions. Now I do have about 127 volts average (Did you know you can buy actual 130v incandescent lightbulbs? I learned that real quick after moving in here and going through too many normal bulbs in the first 3 months.) so I do use my variac when possible. Otherwise I warm a tube up on the next lower setting for 2-3 mins and if it tests marginal I'll bump it up to the listed position and see if it makes a difference. So far everything that tested marginal on the lower setting hasn't improved on the "listed" setting at 10% overvoltage average.

Now for something like a 35Z5 it lists the 25v tap position, so I don't bother warming it up on 12.6 because I'm still short 10v or so at the listed position. Some day I'll acquire an actual tube tester with lots of levers... Someday...


Related morning thought: 115v position, Was that really a common filament rating at some point in the 60s? It does have compactron sockets, and if anything was nutty enough to use a 115v filament (That wasn't a rectifier.) it'd have to be a compactron...

Has anyone tried to calibrate one of these things? I mean just improving the overall accuracy, not anything excessive like you'd do for a scope or VTVM... Seems to be a calibration pot inside, and the manual mentions factory re-calibration. I'll take any tips I can before pushing into new territory and experimenting myself.



From my experience with a Heathkit cap tester and looking at the CB-1-60 schematic, if there is a pot inside it isn't stock.
The only stock calibration on the Heathkit involved loosening the dial shaft lockscrew while measuring a know capacitor and moving the dial until it shows the correct value. I would use a value near the middle of the middle range. I ordered a 5% cap from Mouser (or was it Digi-Key?). If the other cap ranges are then off then the bridge reference cap value(s) would need to be changed. If you are going to re-cap the bridge cap I would use 5% anyway.

Agreed,

There is/was no calibration inside the CB-1-60 other than the position of dial knobs on the P.F. and main R/C pots. Regarding the resistors and precision caps in the Wien bridge; I went with 1% metal film & polyester types for best performance/accuracy.

Tom (PK)

Related morning thought: 115v position, Was that really a common filament rating at some point in the 60s? It does have compactron sockets, and if anything was nutty enough to use a 115v filament (That wasn't a rectifier.) it'd have to be a compactron...

I don't know of any compactrons that have a filament voltage above 40V.

There was an octal 117L7 (?) that contained a rectifier and a power pentode that was made for '1 tube wonder' phonographs before selenium rectifiers became common in cheap phonos.

Allrighty! Providing the last of the components arrive in time, I'm planning on using the 3-day weekend to overhaul my unit. Expect updates then!

I don't know of any compactrons that have a filament voltage above 40V.

The 58HE7 and 53HK7 HOT/Dampers are the only ones that come to mind.

Just curious on the overhaul project; are you going to do a total re-cap, re-resistor, and re-wire job on this unit? To me, once I unsolder a component in a tester like this one's 70 year old vintage, then "it" gets replaced; even the oldy/mouldy cloth covered wiring. About the only things I kept on mine were the "hard" parts including the still V.G.C. terminal strips. To me "soft parts" include inferior/old style aged and designed caps, carbon comp & some wire wound resistors, cloth/tar wiring, rubber grommets, etc.

Tom (PK)

Just curious on the overhaul project; are you going to do a total re-cap, re-resistor, and re-wire job on this unit? To me, once I unsolder a component in a tester like this one's 70 year old vintage, then "it" gets replaced; even the oldy/mouldy cloth covered wiring. About the only things I kept on mine were the "hard" parts including the still V.G.C. terminal strips. To me "soft parts" include inferior/old style aged and designed caps, carbon comp & some wire wound resistors, cloth/tar wiring, rubber grommets, etc.

Tom (PK)

:beerchug: Shipment of parts from Mouser scheduled for Friday arrival, so Saturday if something goes wrong.

My current plan is to replace most of the caps, (I ordered replacements for them all, but I'm going to leave the existing mica in there (C3) as it tests at 190pf with a DMM, should be 200pf.) bridge in a leg to bypass the open section (R7) of my candohm, and slap a new line cord on for evaluation purposes and then :smoke:test it. I bought a few high precision caps, basically 1, 3, and 5 on the scale (so about 25%, 50% and 75% rotation wise on the knob) of all 3 ranges and I'll see how it performs. My thoughts are that the knob might have been "calibrated" with the mica at 190pf. I plan to take the knob off and lift the dial plate out so I can remove any rust between it and the actual steel chassis it hides, but I want to ballpark it with the knob as it has been for many decades first.

I'm planning to go poke the resistors associated with the eye-tube this morning, and see if I should replace them right off too. (The 1 meg on eye tubes "usually" is way off, we'll see how mine is.) Edit: The 10 meg is 12.17 megs (so 22% off) and surprisingly the 1 meg is 1.08 so 8% off. I'll sack them both in the first barrage...

Basically the only discrete parts I didn't order up are the R1 and R2 precision resistors. For two reasons. First: I'm not sure what the wattage needs to be. Second: I'm not intending to use the resistance functions of the unit, because a DMM can do that with orders of magnitude more accuracy and not deplete the life of my eye-tube in the process. Mine also seem to be well within 2% when I measured them so it might function within spec on the old resistors anyway.

The wiring in mine seems to be in fine condition, if it was the early rubber covered type and brittle I would probably re-weave the wires.

I picked up a tube of Simichrome at the awesome local hardware store that's over 100 years old and usually has "everything" if you look hard enough, and I'm thinking I can bring my "Goats" back to a shiny life with it. Cotton or Microfiber? I'm thinking cotton because the MF will probably just trap the Simichrome in the fibers instead of rubbing it on the corrosion...


:worthless
They're coming! Soooooooon!

Where did you find the precision caps?

Where did you find the precision caps?

More or less I just drilled down in the parametric search on mouser, but there's a bunch of 1% 500V units.

Basically drill it down as package type, so radial and axial, pick a voltage, then poke what precisions are available in your desired value range...


http://www.mouser.com/Passive-Components/Capacitors/_/N-5g7rZscv7?P=1z0x86rZ1z0wljoZ1z0z7l5


If you mean where did I find the precision caps used in the bridge itself, here's what I got.


http://www.mouser.com/Search/ProductDetail.aspx?R=ECW-F4205HLvirtualkey66720000virtualkey667-ECW-F4205HL

http://www.mouser.com/Search/ProductDetail.aspx?R=BFC241972004virtualkey5942000 0virtualkey594-2222-419-72004

http://www.mouser.com/Search/ProductDetail.aspx?R=CD15FD201FO3Fvirtualkey598500 00virtualkey598-CD15FD201FO3F

Yeah, the big one is 3%, I couldn't find a suitable 2% that was both in stock and < $10. When I have a bit more money to toss around I'll look into it. :)

Not like it's any major job to open it up and upgrade precision, 10 mins, tops.


Package is out for delivery! :naughty: Hopefully before 1400...

https://www.youtube.com/watch?v=1lpLAjZMj90


IT LIVES!


My can of ohms got really really weird when we unmounted one end to pop in a terminal strip, so the original plan of just fix the last segment being open turned into the full "pull it out and re-make it." In the future I'm going to go back and re-dress the wires and generally make it look a bit less of a lash-up, but it functions!


http://www.funkengine.net/solar/Zi6_1475.JPG

http://www.funkengine.net/solar/Zi6_1477.JPG

http://www.funkengine.net/solar/stormwatcher/IMG_4169.JPG

http://www.funkengine.net/solar/stormwatcher/IMG_4165.JPG

http://www.funkengine.net/solar/stormwatcher/IMG_4170.JPG

http://www.funkengine.net/solar/stormwatcher/IMG_4162.JPG

Well,

I wouldn't rate your "restoration" efforts so far as grade "A" seeing these photo's. But then again you said this was a first pass with the new parts. I'd like to see the finished product.

Tom (PK)

Well,

I wouldn't rate your "restoration" efforts so far as grade "A" seeing these photo's. But then again you said this was a first pass with the new parts. I'd like to see the finished product.

Tom (PK)

I'm my own worst critic...

C- on aesthetics.
B on functionality.


The night we planned to do the quick resto became significantly more complicated once the candohm decided to flake out and we had to do major surgery to replace it. I had planned on the first pass to be just add a 7.5k resistor in place of the open section at the end, swap the caps, and fire it up. We wound up replacing the bias resistors, and having to reconfigure the wiring with what little I had handy at the time. The patient lived, but is horribly disfigured...


I've been a bit... distracted... lately. :banana: Pictures shortly as to why. (Spoiler: :yes:Rigol.:yes:)


I have grand plans for my CB-1-60. Soon it shall become the CB-1-60 Mk II. With any luck it will survive another 60+ years. (Yes, I'm honor-bound to remain true to the original design. I'm making some slight modifications, but by :nono: means are we talking paint or transistors. There might be a diode involved, I haven't quite decided on that bit.)

Here's a bit of a teaser since I've had some time to work on my plans with the holiday and all...



http://www.funkengine.net/vk-img/2014-07-05/mkII.png

Here's a bit of a teaser since I've had some time to work on my plans with the holiday and all...

A teaser to say the least. I'm not familliar with that software, but it certainly leaves me wondering (from a textbook electronics standpoint) what I am looking at. Not trying to be a smart a** or anything. It looks like you could use a program like MultiSim which is an actual electronics simulation program where you can select and place components with correct symbols for resistors and term references for capacitors ie. uF and so on and so forth.

After you place your components, you simply connect the "dots" with virtual wiring and flip a virtual toggle switch on and virtually see what your design will do with virtual meters for R, I, E, and even a P meter! Oh, and a scope to boot! Anyway, well worth it if you are into circuit design and presentation.

Maybe my teachers and professors were too picky.......:scratch2:

A teaser to say the least. I'm not familliar with that software, but it certainly leaves me wondering (from a textbook electronics standpoint) what I am looking at. Not trying to be a smart a** or anything. It looks like you could use a program like MultiSim which is an actual electronics simulation program where you can select and place components with correct symbols for resistors and term references for capacitors ie. uF and so on and so forth.

After you place your components, you simply connect the "dots" with virtual wiring and flip a virtual toggle switch on and virtually see what your design will do with virtual meters for R, I, E, and even a P meter! Oh, and a scope to boot! Anyway, well worth it if you are into circuit design and presentation.

Maybe my teachers and professors were too picky.......:scratch2:

Oh, its not a SPICE sim. That's a PCB layout. (Although I have considered entering the entire circuit in and seeing what SPICE makes of it.)


Here's what the schematic looks like (I didn't bother cleaning it up, I just needed it electrically correct and component-correct so that I could lash the whole thing up as a PCB.)

http://www.funkengine.net/vk-img/2014-07-10/mkII-v0.2-schem.png


There's no spoiler tag option installed here at VK so I have to transmit this in the clear I guess...


Hint: Look at the component numbers, and then go look at the CB-1-60 schematic...


Here's a teaser that has no airwires pictured and also has the traces on the correct side of the copper for through-hole components. I still need to pop things apart and take some mounting and clearance measurements before I decide the final shape/size of the board and where to place the mounting holes on it. I'm also holding off on designating the isolation slots to be milled out until I revise the layout more based on measurements, but be assured I am taking the fact that there's ~500VDC on this board into account.

http://www.funkengine.net/vk-img/2014-07-10/mkII-v0.2.png

It looks like there was a "pilot error" in your CAD drawings regarding C6 and C7 and their polarity thereof; (LOL) and magic smoke would result...

http://www.allaboutcircuits.com/vol_1/chpt_13/5.html

Also, why all the bother of doing a 21st century PC board when a simple time period correct 8-way terminal strip will do the same function (and terminal strips were how it was done; construction at the time) to somewhat maintain the authenticity of it? How far does one go with a restoration or a total re-engineering of this type of vintage gear? In the 1940's when this unit was produced, man-kind had no idea of how PCB materials like FR-4 would eventually revolutionize the electronic world of construction.


Tom (PK)

Yep, non-polarized film caps though, I just needed the right package style for pad placement and spacing. (Strangely the board layout icon is non-polarized but the schematic capture icon is...) If it were a polarized package style one of the pads for the caps would be square to indicate polarity. I'll have to play around with some of the other cap options and see what else is "not accurate."

As to why I'm going with a modern PCB style upgrade, the board will evolve over the next few weeks. I'm adding the ability to change the target voltage on the eye tube, and maybe one or two other things, including possibly adding a 1µF to "700"µF range. (700 only because that's the normal scale max of "70" x10, I honestly don't expect accuracy out of it, but I'll see what I can do.) The target voltage taps are for two reasons. First, to preserve the life of any eye tube by running it at a lower voltage that provides adequate brightness. (probably +160). Second, having higher taps (I'll go as high as +260) will allow one to use an already mostly worn out eye tube right down to the final nub of darkness. This considers a future where there are no NOS eye tubes available at any price, all have been used, some a lot more than others.


The process of testing these changes will be very ugly, but once a working system has been achieved, boards will be made, components attached, and wiring replaced with some new manufacture cloth-covered wire. The goal is to have an intelligent blend of old and new.