1050 Disk Drive Repair Question - Runs fine for first minute then turns itself off

[vdub_bobby]

Apologies if this has been asked already; I did several forum and Google searches and couldn't find anything that matched what we are seeing.

 

I've had a 1050 (w/ 130XE) since I was a kid, and always worked fine.  Now my kids like to play around with BASIC programming, and after a year or so of use the 1050 disk drive is no longer working, kind of.

 

What happens is the first time (in a day) that you use it, it runs fine for about 3-4 minutes - loads software, etc. - but then it just turns itself off.  Drive stops spinning, LEDs go out, right in the middle of loading something from the disk.

 

After that, you can power cycle the drive and it will work again, temporarily, but not as long - less than a minute, usually.

 

Any ideas?  I haven't had a chance to crack it open yet and poke around.  Thanks!

Edited February 18, 2023 by vdub_bobby
typo

[Beeblebrox]

Possible the capacitors in this need replacing perhaps? 

 

Can you open it up when unplugged  and carefully have a look at the large caps to see if bulging or leaking present? Don't touch them! 

 

Also the caps could have developed a dry solder joint. When they heat up and the solder expands maybe a connection is lost. I had this once. Re flowed the solder on the underside and it was OK. 

 

Also might be a similar thing with the chips in their sockets. (Chip legs can oxidise and heat/expansion can cause poor connections. Dry joints on the socket's solder connections with the PCB etc.

 

You could try reseating chips which can improve the situation if oxidisation is present. 

 

Of course maybe a chip itself is failing. 

 

Not got enough experience with fixing drives as only fixed a couple. There are some real experts here on AA who I am sure will chime in on this topic. 

Edited February 18, 2023 by Beeblebrox

[thorfdbg]

2 hours ago, vdub_bobby said:

I've had a 1050 (w/ 130XE) since I was a kid, and always worked fine.  Now my kids like to play around with BASIC programming, and after a year or so of use the 1050 disk drive is no longer working, kind of.

 

What happens is the first time (in a day) that you use it, it runs fine for about 3-4 minutes - loads software, etc. - but then it just turns itself off.  Drive stops spinning, LEDs go out, right in the middle of loading something from the disk.

 

After that, you can power cycle the drive and it will work again, temporarily, but not as long - less than a minute, usually.

That's a typical indicator of a power problem, induced by a thermal problem. The 1050 runs on a 9V AC adapter, which goes into a rectifier and voltage doubler circuit, generating both 5V for the digital components and 12V for the analog components. This circuit is known to have some "issues": First of all, the diodes in the rectifier are under-dimensioned and like to burn out. They can be easily replaced by off-the-shelve parts, just with a higher current rating. Second, the capacitors in the rectifier/doubler circuit also age and dry out. They can also be replaced. Also standard components, not hard to find.

[macsonny]

On 2/18/2023 at 7:11 PM, thorfdbg said:

That's a typical indicator of a power problem, induced by a thermal problem. The 1050 runs on a 9V AC adapter, which goes into a rectifier and voltage doubler circuit, generating both 5V for the digital components and 12V for the analog components. This circuit is known to have some "issues": First of all, the diodes in the rectifier are under-dimensioned and like to burn out. They can be easily replaced by off-the-shelve parts, just with a higher current rating. Second, the capacitors in the rectifier/doubler circuit also age and dry out. They can also be replaced. Also standard components, not hard to find.

I was going to say something similar. Check the two rectifiers (7805 and 7812). I had one act a little funny because the unit was on the way out and the 30+ year old thermal paste was all dried up. Might be worth replacing them if you can. Not too difficult a job.