tt-5 5BP4
 

I got the TT-5 I won at the ETF auction home and inspected it.

The CRT plug, if it is a socket, is falling apart. The wires are
100% OK however. It can be fixed.

BUT .. I can't figure out how the socket comes off! There is no
groove between the socket and what would be the plug if it were intact.

It is not the normal Bakelite plug! Its a very thing shell which appears
to be in two sections. Its hollow inside the the wires just flop
around. How does this thing work? It looks like I could grab
the shell and push of the inner keyed piece ... but I'm very afraid to try this.

What should I do?

Otherwise, the set look in good shape.

Photos might help so we can see what is odd about it.

.

Ill do that tomorrow. Tonight I finished
the project I was working on before the convention: a
set of switchable filters for Sw SDR radio. They make
a lots of aliases go away.

I figured it out with help from photos of tubes on the 'bay. Its a very bad socket
design, as you can't grab the actual plastic base to hold it as there is a lip
on the socket covering it up. I had to slowly pry my socket off with two screwdrivers.

The HV wires to the socket are dangerously old ... they are beginning to crack.

I have ordered new wire.

But how do I remove the contacts from the socket? My guess is that I
unsolder the old wire and pull it out, if it comes out. Then there are likely
little "spurs" on the contact that I need to push out to get it to came out.

Has anybody redone the wires on the CERT socket on one of these?

On the other hand, they are all clearly good enough and at close enough voltage,
that I could just wrap the whole bundle with cut-open vinyl tubing and cable-tie
it together, to protect me.

Where did you find the wire? I tried looking for replacement wire a while back and could not find anything.

Up to 10 kV Mouser has it. Odd place.

Go to manufacturer Pomona. Then search for wire. They have it
in 5 and 10 kV red and black, 50 foot lengths.

Above 10 kV I can find the manufacturers but no distributors.

and, of course, there's ebay

Above 10KV there is always the old rob the HV wire from a BPC CRT set sitting by a curb or in a field method...

Automotive spark plug wire (the non-resistive type) is another option, and should be available at the local auto parts store of your choice.

Argggggggghhhhhhhh

Abysmal soldering job throughout this set ... right from the factory.

Big blobs of 50-50 or worse solder!

I can't even use a solder sucker without first adding 60-40 solder.

Sorry, should have been more specific, I was looking for an exact replacement for the multicolored rubber coated wire. I know I can get a functional replacement.

Well, there is black, white and red on ebay. They are quite close looking.

I found all the other colors, at their manufacturers. But no distributors.

TT5 restore thread
 

My tt-5 restore proceeded well until this evening.

I recapped the HV section and all electrolytics plus a few
critical paper caps.

I then turned it on using a variac and dim bulb. Nothing sparky or
smelly happened. The HV section works ok as tested with my new HV probe.
The B+looks OK at slightly reduced line voltage.

The horizontal works fine.

The vertical is dead, apparently due to an open oscillator transformer
primary (plate) winding. This needs to be verified and if so checking
for bad wire connections.

Its supposed to be an RCA 32898. Can these by found? If not,
the circuit looks rather common, I've seen similar circuits
with different transformers. Is it possible to use a different replacement,
or find the specs to have this one rewound? would a generic 4:1 one with
appropriate resistances work (properly)?

Doug McDonald

An attempt to fix the transformer failed. Indeed there was a break at the small-wire
lead junction. However, the fine wire broke off at the paper.. Further investigation
showed that there were multiple patches of
corrosion in the few of layers of wire. Something
corrosive was there from the day of construction.

Sulfides from the paper? May be just an old wives tale, but several radio collectors that I know claim this is a real problem on pre war radios.
Coin collectors also seem to avoid paper envelopes for the same stated reason.:scratch2:

jr

I don't think it was from the paper. On the windings it was patchy and seemed
to be coming in from the edges.

Another symptom was that it was impossible to solder to the lead wires using
just solder and flux! Period. No matter how hard I tried. There was some sort
of coating that resisted heat so well that even my hottest soldering iron
setting and liquid flux could not beat it. It had to be scraped off. A sulfide
would dissolve in flux.