Help with Triplett 3444 Restoration

[Fotomeow]

hey all,

I have a Triplett 3444 that is not working as I expected or as I wanted !
I have been following the Triplett instructions straight from the original manual that I downloaded.

1. The power comes on, lights in the meter and roll chart work ok.
2. The Line Test is fine.
3. But then the Gm test does not swing the meter dial all the way to the right “full scale”.I push and turn the Gm knob as instructed.

I started cutting out the big yellow caps to replace them, but that is about the extent of my technical skills. Im reading more and more about the problems with the 3444 restoration, so Im gonna need some help doing this.

I have spent hours on the net looking for a guide or forum to help me restore this 3444. I have not found any guides, just bits and pieces in forums by more experienced technicians than I.

Any suggestions? Know anyone else with a 3444?

Thanks! Gary

 

[Osvaldo de Banfield]

Are the windings of the transformer(s) OK, read the DCR with a VOM without power it, then make a current limited power supply (It is easily done placing a filament lamp in series to the live wire of the power cord, or still better, in a box properly terminated. I insist, filament or incandescent lamp, not led or fluorescent. Us e a lamp of the same power drawed by the DUT, as an intial guidance). Then, check the power drawing observing the bright of the lamp. If the DUT has been much time ago stored, then let the transformer to heat lowly to get rid of the humidity accumulated in it.

Then, start measuring the AC voltages at the secondaries, many of then will be present at the sockets for tube heating. It appears to me to be a tube tester, so, from 1.2 to 117VAC are needed for most tubes available. Warning, may be dangerous voltages in the set, including some faulty components that placed high voltages where usually aren't.

 

[Fotomeow]

Replacing Caps

Hi Osvaldo,
Thank you for the advice, I will try that.

today, I was just trying to replace 6 big barrel capacitors..
I cut out the 6 big yellow caps, got the specs,
and looked them up on the web. I've found 5 of the 6 cap replacements.

The 6th one was the biggest - a 50uF/350VDC, they are about the size of the M80s we used to get from the Indian Reservations around the 4th of July. But hopefully these won't blow up!

In any case, I have found a few 47uF/350VDC, and Im wondering if the 3uF difference b/w the 47 and 50uFs is significant, or not?

O/w, the closest I can find to a 50/350 is a 50/450VDC, a 100VDC difference.

Which would be better/worse (depending on how one looks at it) to replace the 50/350 with:
A. the 47uF/350VDC or
B. the 50uF/450VDC ?

IMG_9834.jpg

 

[Fotomeow]

3444 transformers

oh, and these are pics of the underside of the tube tester and the transformers.

 

[Osvaldo de Banfield]

68µF @ 400V?

In any case, you can take two alternatives:

1) worst case: 47µg @450V. This is not the best solution if voltage there si, for example, 200V because the cap will not form completely. It is safe, but nor technical correct completely.

2) Take a measure with a test cap and the voltage present (For example, one of that you found), and then put the nearest cap value with the nearest voltage rating. Let's suppose than there, there is 270VDC. Then, a 450V will not preform pretty good. In such a case. I would prefer a 300VDC unit, or still a little worse, a 350V one.

Transformer looks good at first instance.

In any case, I strongly suggest to work with a series lamp.