TI-99/4a: Do we need to replace the elect. capacitors in them?

[AMenard]

Hi,

 

I'm just wondering if the TI-99 needs a full recap like other computer of those time. On my Atari 130XE it's an easy task with just 5 of them present on the board, but since I didn't crack open neither of my TI-99 I'm wondering how many of the are in need of preventive replacement?

 

If we do have to replace them, is there a list or BOM available?

 

Thanks.

Edited December 19, 2017 by AMenard

[AwkwardPotato]

I'm not exactly an expert as far as caps go, however from personal experience, I've never run into any cap-related symptoms with any of my TI gear. The only machines of mine where caps seem to be an issue are 68k Mac's, Amiga's, Atari ST's, etc. from the late 80's onwards.

[AwkwardPotato]

Here's a list of capacitors just in case:

 

Motherboard:

5x 22uf 25v

3x 100uf 25v

1x 10uf 25v

 

Power Supply:

1x 4.7uf 50v

1x 470uf 12v

2x 47uf 16v

1x 1000uf 25v

1x 3300uf 35v

 

One thing I'd like to mention is that these may just be the values for my particular revision of the PSU and/or motherboard.

 

I'd also imagine that the challenge as far as recapping the TI-99 goes would be finding axial capacitors instead of radial.

[AMenard]

Thanks!

 

I've opened my beige yesterday for something unrelated and checked on them while it was open. No signs of leakage or bulging that I could see so I guess it can wait. I'll probably do it on my second TI (aluminium) since I have a couple of things to fix in it, like a sticky switch and a loose video port.

[Swim]

Thanks!

 

I've opened my beige yesterday for something unrelated and checked on them while it was open. No signs of leakage or bulging that I could see so I guess it can wait. I'll probably do it on my second TI (aluminium) since I have a couple of things to fix in it, like a sticky switch and a loose video port.

 

Yes, I have been doing repairs on TI/Geneve boards for a while now and broken video/audio solder joints rank right up there with bad TMS9901 and TMS9918 as common repairs.

[AMenard]

Yes, I have been doing repairs on TI/Geneve boards for a while now and broken video/audio solder joints rank right up there with bad TMS9901 and TMS9918 as common repairs.

I'll give it a complete checkup next week.