Bad power supplies, why so common, what to do with them now

[CincYnoTi]

I'm testing consoles today and am amazed how many power supplies are bad. I've tried eight PS so far and four of them seem to be dead. What is the common failure point of these? 

 

I doubt I would ever do a repair, but I see non-working ones on ebay selling for $20 and working ones going for $45-50. Anyone here do repairs?

[+slx]

Best Electronics sells new PSUs  for 21 USD plus shipping and claims they plugs are more durable than the originals.

[+DrVenkman]

The 7800 input is just 9VDC. Nothing fancy about it at all. The only tricky part is that stupid non-standard connector. You can easily replace that with a barrel jack and use any 9VDC PSU you want so long as you watch the polarity. Alternately, you could go nuts and get a 5DVC PSU, then remove the 7805 and heatsink while you’re at it, running the input straight to the output side where the 7805 was located.

 

Plenty of ways to work around this issue. 

[+-^CrossBow^-]

1 hour ago, CincYnoTi said:

I'm testing consoles today and am amazed how many power supplies are bad. I've tried eight PS so far and four of them seem to be dead. What is the common failure point of these? 

 

I doubt I would ever do a repair, but I see non-working ones on ebay selling for $20 and working ones going for $45-50. Anyone here do repairs?

The main issues with the 7800 PSUs is that the cable internally becomes frayed right inside the stress relief section where it is connected to the plug end that goes into the console, or at the wire base where it goes into the PSU itself. As they are sealed, you would have to cut them open to try and attach new wire etc. So I think it is best to either go with Best Electronics replacements, or as @DrVenkman stated, you can convert it it to use something that is easier to get a replacement PSU for.

 

[juansolo]

Quote

I'm testing consoles today and am amazed how many power supplies are bad. I've tried eight PS so far and four of them seem to be dead. What is the common failure point of these? 

This goes for all old kit. Original PSUs are 30+ years old. Electrolytic capacitors, by their very nature, have a finite life. They either dry up or leak eventually. Ones in PSU's are generally exposed to heat, and that shortens that life. Next, storage plays a part. There are some brands that are notorious for catastrophically failing with age (RIFA), not so much an issue with Atari stuff, but they've been the death of many a BBC Micro.

 

Store something for years somewhere humid and corrosion is your next problem. Effecting wires and contacts. Plastic also degrades and can do wierd stuff over time, again making cables rigid, couple that to potentially corroded wires inside are a recipie for broken connections. Generally speaking I do not recommend using original PSUs on old kit if it can at all be avoided. If not I will always at the very least test them, and if possible replace parts that have potential to cause problems. The thing that can cause problems there is that a lot of old PSUs are encased in resin rendering them irrepairable.

 

Modern PSUs come in two categories, the first is cheap switched mode stuff, usually from China. Do not use these on your old consoles. Sure there might be some that are ok, but lots of old consoles had proper bricks of a PSU with proper transformers and nice big caps in them to smooth the power coming out of them rather than having them inside the consoles. Having an SMPS without adequate smoothing can cause all manner of issues with old kit (usually piss poor picture, but they can cause other issues also). The second type are known brands that cost a little more like Meanwell. Their stuff is consistently well made using quality parts and often make great modern replacements for old PSUs. There are other options of course which will vary from country to country depending on your supply voltages and what have you.

Edited April 26, 2023 by juansolo

[SearsRoebuck]

Personally, I swear by Retro Game Cave's ACs.  Nothing but good to say about his newly manufactured 7800 AC:

 

https://www.retrogamecave.com/product-page/atari-7800

[harmonyFM]

I've still got the stock PSU for my 7800 that it came with, do they have reliability issues? I've never heard this before.

[Trebor]

6 hours ago, harmonyFM said:

I've still got the stock PSU for my 7800 that it came with, do they have reliability issues? I've never heard this before.

Considering it is 35+ year old hardware, YMMV.   Factors including, but not exclusive to, any type of (non)abuse it may have encountered, including (storage) environment(s), will typically play a significant role.

 

The OP's experience has been different than mine, as I have five original stock power supplies, none have issues.

 

Nonetheless, I am pondering to order at least a couple, of what was mentioned earlier.  They are brand new/better than OEM from Best Electronics:

 

The New 2018 boxed Best Auto switching Upgraded / Enhanced Atari 7800 Power Supply with the normal 90 day Atari Warranty.  

Part No. CA025492-303   Model No. CX781  USD $21.00

 

E-Mail is probably best: bestelec@bestelec.digitalspacemail8.net
Though phone is available too: 408-278-1070 (1:30 - 5 PM, PST, M - F)