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Need help finding a replacement transformer for console game

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eobard

Give me a break Senior
Joined
Jul 12, 2001
I've been sitting on an old Intellivision console for about six months now and as I finally get around to trying to get it working I find that the transformer for it is dead. I've checked online and the consensus is to get a replacement instead of trying to fix the original. The thing is no one in my local area has anything compatible. I've been to surplus stores, electronic component stores, flea markets, etc. and no one has what I need. The transformer I need is wired like this: 120vac on the primary side, the secondary side has two sets of outputs. One is a straight 18vac and the other one is 18.5vac with a centre tap giving 9.25vac between it and either of the ends. I've looked at digikey and a few others but haven't seen anything fitting the specs I need. I'm not even sure what the technical description for what I need would be. Single winding primary, dual winding secondary with center tap? Would that be right? I've checked ebay, no one sells just the transformer and shipping for the entire console is cost prohibitive. Any hints on what I should do next?
 

Bobnova

Senior Member
Joined
May 10, 2009
What I would do, and this is just me, is crack open the console and see what it does with those voltage inputs.
If it rectifies them into DC immediately you could find a DC power brick or two with something like the correct voltages and wire that up.
 
OP
E

eobard

Give me a break Senior
Joined
Jul 12, 2001
It does lead to a voltage circuit board which then modifies it to a series of different voltages for the motherboard.... Can't find the PDF listing them nor do I remember them off the top of my head but I'd rather just replace the single transformer than monkey around with getting 4-5 different voltages to the mobo from different sources anyway.
 

johan851

Insatiably Malcontent, Senior Member
Joined
Jul 24, 2002
Location
Seattle, WA
I bet it doesn't need to be that close to the transformer voltage, then. The rectifier and DC regulators will have a little bit of headroom so they never drop out of regulation. It should be alright to get something with slightly higher voltages, or maybe just a 18/18 VAC with a center tap.
 

Bobnova

Senior Member
Joined
May 10, 2009
Totally understandable!
I'm going to look around and see if I can find anything, thing has to exist somewhere.
Any idea what kind of amperage?
 
OP
E

eobard

Give me a break Senior
Joined
Jul 12, 2001
The listing in the repair manual matches what I've seen in Youtube videos on repairing the system but the stats listed on the actual transformer in my unit don't. The wires coming out of the transformer are colored as follows:
Blue (B) - Yellow (Y) on one winding
Green (G) - Green w/yellow stripe (Y?) - Green (G) on the other winding, with the yellow stripe being the center tap.

The transformer has the following stamped into it's cover:

G-G / Y-G
15V 12.9VA
B-Y 14.5V 7.25VA

The official repair manual shows the output from the power circuit as follows:

+5V
+12V
+16V
GND
-3.3V

A popular website with repair info for the Intellivision system lists the following voltages (same pin out order):

+5
+12
+16
GND
-2

As you can see the fifth value is different but the guy at the site linked to above really seems to know his stuff so I don't think he's off, could be just a typo or within tolerances. Can't find the third reference rolling around in the back of my mind but I did see -1.7V listed as the value for the fifth pin somewhere else, don't remember if any of the other values were different.

No idea about any of the amperages. Can't be too demanding. We're talking Atari 2600 era technology. The very first PC's, 8088 processor XT's, ran fine on sub 100watt PSU's and this system has a lot less to it than one of those did.
 
OP
E

eobard

Give me a break Senior
Joined
Jul 12, 2001
Long time old bump. I'm back into working on this to see what I can get done. I've now got two transformers hooked up to it in place of the multi-output single transformer. One supplies 18v, the other supplies 18v with a center tap for 9.5v. I've now tested the output after the first board, which regulates the powersupply, and have encouraging results. On the output pins from that board all but one pin give results in range. The voltages I'm getting are

+5v
+12v
+33v
0v
-2v

So the first, second and fifth voltage pins are spot on. The ground is ground. The only thing off is the third pin. It's supposed to be 16v but I'm measuring 33v on my meter but it's supposed to be 16v unregulated, so it can float depending on the draw. Is 33v reasonable given no draw other than the meter in this circumstance?


addendum: Man this place has changed a lot since I started this thread. I don't know for sure if belongs in this area anymore based on current sub-forum structure. Mods feel free to move this to Power Supplies and Electronic Devices if you feel it belongs there instead.
 
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