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Elwro Ameprod TVG-10 pong console transformer voltage

grzybek

New Member
Joined
Jul 1, 2020
Messages
3
Hi,

Do any of you guys know the parameters of the transformer in Ameprod TVG-10 (old pong console made by Elwro on AY-3-8500 chip)?
Mainly, I would like to know the voltage on the secondary winding of the transformer.
I know from the internet that it is a four-watt transformer with a double secondary winding. Model from the TS4 series, but I don't know the exact number (TS4/??).

I would like to revive this pong, but the said transformer is broken... and so I am unsuccessfully seeking info about it, because I do not know which one should I replace it with. :( I didn't see the schema over the web either.
Maybe someone has this console and could measure the secondary voltage with a meter?

Thanks for any answers.
 

Chuck(G)

25k Member
Joined
Jan 11, 2007
Messages
38,896
Location
Pacific Northwest, USA
We'd have to know how the transformer is used (i.e. trace out the PSU circuit) before we could even guess.

When you say that the transformer is "broken", exactly what do you mean? Some inexpensive consumer-grade transformers have thermal fuses which can be replaced or bypassed.
 

grzybek

New Member
Joined
Jul 1, 2020
Messages
3
Well, the primary winding is cut in several places. :p
My dad, years ago, tried to cut the insulation in the primary winding and of course he cut too deep. ;)
I don't think I can repair the winding in any way, so I thought I'd replace the damn thing. But there's nothing written on the part (except the console model "TVG-10"). There's no termal fuse, at least on the primary side (maybe it's taken out or something).

What I read on the web is that everything except the speaker was powered from a serial voltage stabilizer on the BC211 transistor with a zener diode in the base. The base was supplied from the collector, through a 430 Ohm resistor. The zener diode was probably 7.5V, but that's unclear. After the whole AC to DC conversion and stabilization, the voltage supplied to the chip was 6,8V which is right for the chip specs.
Now, my brain can't cope how to reverse engineer all of this to get the secondary voltage of the transformer.
 

gertk

Experienced Member
Joined
Jan 26, 2016
Messages
396
Location
Netherlands
From the datasheet:

The AY-3-8500 was designed to be powered by six 1.5 V cells (9 V). Its specified operation is at 6-7 V and a maximum of 12 V instead of the 5 V standard for logic. The nominal clock was 2.0 MHz, yielding a 500 ns pixel width. One way to generate such a clock is to divide a 14.31818 MHz 4×colorburst clock by 7, producing 2.04545 MHz. It featured independent video outputs for left player, right player, ball, and playground+counter, that were summed using resistors, allowing designers to use a different luminance for each one. It was housed in a standard 28-pin DIP.
So it is not very picky on the supply voltage. If you can bypass the transistor/zener circuit you can use a stabilized 6 to 9 Volt supply and it should work.
 

grzybek

New Member
Joined
Jul 1, 2020
Messages
3
Hi again,
I'm so sorry for not responding for a while. Life got in the way.

I'd like to post the answer to my own question. :lol:

So, for future generations... The transformer compatible for this console is "TS4/024" which is 230V on primary and 2x7,5V on the secondary winding. You just need to join together the two center pins of the secondary winding and thus making a center-tapped transformer out of it.

I also replace all electrolytic capacitors just in case (they were about 35 years old... xD). My pong now runs.
Now I need to figure out how to convert it to cinch cable. I would like to have both cinch and "normal" antenna cable for old TVs.

Thanks, guys for your inputs and trying to help. Live long and prosper!
 
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