AVO 2 panel dangling components location

[dfriedman]

Hi - I need help w/ this tube tester. I own quite few which I've calibrated: AVO 3, Triplett 3444, Eico 667 & fixed a Taylor 45D2. Currently working on a TV-2(requires a fil mtr - I'll fit from another mtr). I also own an AVO CT-160(requires a new mtr(which I'll fit from a Yokogawa mtr), few Hickok types a Jackson & more.
This 2 panel AVO, got from UK as working, via eBay global shipping - arrived w/ lose pieces inside. The seller didn't pack properly - it was so very lose in its wood case. eBay refunded me all the money I'd paid for it - including shipping.
My problems:
- The rectifier was off its soldering, but its assumed place, as I can make out from its soldering location doesn't make sense per schematic.
- The C5=.05 was a combination of 3x .02.
- A lead was cut & a .05 cap was added in series. I've to find where it was added in the schematic.
- Another .05 cap was added. I've to find where it was added in the schematic.
- These last 2 caps don't show in the schematic. C5 is in the right location.
So, can anyone post pictures of the innards, especially of the rectifier's location - they've to be close pics, because the pics online don't show its location?
Thank you in advance, Dany, Toronto

[martiR2R]

Let me know which of these 3 is most like yours and I'll try and take some close-ups - it'll take a few days before I can post the results.

Regards

Martin

[dfriedman]

Thank you Martin. Your pics - from Left to Right, picture #3 shows the Rect, but doesn't show its polarity, i.e. which side is the rec is +. I'm going back soon to the basement to figure out by comparing to the CCT.
Now to my pics - I hope they're in the right order:
- shows another mysterious .05?

- shows a mysterious .05 cap inserted in series of a cut lead - what's this?

- shows C1 - I installed.

- shows the Assumed polarity of the Rect, by the way of soldering marks.

- shows the assumed [place of the Rect.

These 2 "extra" caps are my replacements, since the 2 caps broke in shipping from the UK! However, the CCT only shows 1 cap = C1.
Dany, Toronto, Canada

[Freya]

This will probably be of most help.

[dfriedman]

Thank you Stephen - I've now figured the polarity of the Rect w/ the help of your dwg's = as per my pic 4.
However, I'm still puzzled about the extra Caps I'm showing in pics 1 & 2 - they're not on the 2 Schematics of the AVO I've! Perhaps you or someone else can fire some pics showing the location of these 2 Caps. I can see in your attachments extra Caps, though.
Dany, Toronto

[chriswood1900]

Dany
I think I have realised why there is some confusion about the circuits and capacitors, you mention that it came in a wooden box, I assume this has the tester in the base and the valve holder panel in the lid.
This is usually what is know as the Admiralty Pattern which supplied to the Royal Navy which has a different circuit employing a cutout along with an additional capacitor.Shown in photo 1 below.
Useful info is here:-
http://www.vmarsmanuals.co.uk/archiv...ultfinding.pdf

An overhaul I did with some pictures is here including the setup instructions.
https://www.vintage-radio.net/forum/...ighlight=panel
Good luck
Chris

[Freya]

The redrawn schematic i attached shows the additional components in the admiralty version with the cutout lamp etc.

[dfriedman]

Hello Chris & Stephen
Mine is probably the Admiralty version, as it comes in a Grn wooden case(which's cracked) & has a small metal plate attached, whose writing is marked off. There's a Cutout device inside.
- Chris - your pic accounts for 1 cap, but my pic 2 shows another Cap?!
- Stephen, you aren't showing the "redrawn" schematic here.
- Another problem is that the 1/6 WB rectifier is shorted - it only passes AC & heats when I place a 2.2 uF cap across it - @ 120v. I've a small Selenium from a small tube radio to replace it w/. I could replace it w/ a 1N4007 & an suitable resistor, but I'll have to cal it - @ least not yet.
- In the description there's also a reference to power w/ 120v, by accessing a 100v connection - but this tester has no such thing - it's only adjustable to around 220-240. I do have few isolation & auto x'formers for 120 -240 = not a problem.
Thank you, so far, Dany, Toronto

[dfriedman]

Hello again
In his 19.4.19 Chris referred me to 1 of his posts from 6.5.18 where he mentions 2 rectifiers!? the regular CCT doesn't show 2 rect's!
Again, Stepehen says he'
s got a redrawn schematic, but not yet posted. Perhaps this version has 2 rect's?
I'm looking fwd for more info. So far I only had the chance to reglue the Sc socket which was broken. I haven't got 1 because it's British dia. I used Armstrong Pro Black 2 component glue = very strong. I'll be back to test the caps in the sockets panel w/ my LC76 cap tester.
Best, Dany, Toronto

[Freya]

The redrawn circuit is in post #4. It covers both actually with the additional circuit layout marked with changes for Admiralty version.

[chriswood1900]

Dany
There are 2 recifiers and they are as Freya said shown in the drawing, MR1 plus one not numbered, I can't remember quite where they were but I will have a look at the weekend and post a picture for you.
I found it useful to print out the schematics and stick them together so you can see the whole layout it then made it easier to sort out.
Chris

[dfriedman]

Hi Martin
Sorry getting back to you so late, but only tonight I realized that you pic has 3 versions.
The most extreme Right is relevant = to my version! So, by all means please post a close-up of that one.
ThanX, Dany, Toronto

[dfriedman]

Greetings to all
The work is proceeding slowly because of other commitments.
I've identified the proper polarity of the shorted Rect - the 1 that had been loose in the case - to be replaced. It's the non marked one.
The 2nd Rect seems OK. I'd to get to it by removing the Cut-Out Rly. It's a bit difficult to install it back - I've to find a way to insert the the triggering pin in the provided hole. Any suggestions? The WW 50 ohms in series measures 47.5.
I also found that the 2x .001 caps in the socket panel were NG - replaced. The 3rd = 25 pF is OK.
I also taped the 4 sections to create 1 dwg - thank you.
Al the best, Dany, Toronto