Faulty 5150 Motherboard

[Cyberstein]

Well, I wish I could have, that would have been sweet. But for some reason the designers of this card thought it would be cool to put in a battery that’s hard leaded. Into what kind of looks like a battery holder. I actually considered trying to desolder those leads and re-solder to new battery. But I decided against it, since it would only be a temporary fix.

 

[maxtherabbit]

Ah I see

 

[NeXT]

Just to share, I also had to repair both Tandon drives on this unit. They had the usual shorted tantalums and what not, which I recapped. And while I was doing this I of course, I oiled/cleaned them. Which is where I noticed the pulley on drive B was severely deformed and cracked. Bad enough where it could not freely spin, prohibiting the drive from functioning. This is the first time I have seen a part any computer do this, especially an IBM. It's almost as if the part is a knockoff made out of clay. I am almost 100% sure this is the original drive that came with the PC, it even has the original box with matching serial numbers. Luckily I have a spare scrap Tandon for parts that I could get a replacement pulley from. I just wanted to share because I own quite a few IBM's with Tandon's and have never seen this before. Have you?

I have. The pulley is made of Pot Metal and the composition is such that from one batch to another the castings may either last forever or turn to dust after a few decades. It's a major issue with older mechanical devices and die-cast toys because it was so cheap to work with and Asia especially manufactured a LOT of small metal components out of it rather than stamping and milling pieces.

 

[Cyberstein]

@Cyberstein / @modem7 if there's any tests you'd like me to perform to verify what you're seeing let me know. I haven't replaced the battery on my card, but I have one I can put on there if needed.

Maxtherabbit now has me wondering. Your battery is hard leaded as well right?

I have. The pulley is made of Pot Metal and the composition is such that from one batch to another the castings may either last forever or turn to dust after a few decades. It's a major issue with older mechanical devices and die-cast toys because it was so cheap to work with and Asia especially manufactured a LOT of small metal components out of it rather than stamping and milling pieces.

Thank’s for the explanation, makes sense. Given everything else in the computer was in excellent condition.