SC1224 Resistor R707 Burned up and smoked!

[Gunnder]

Hey guys,

picked up an Atari ST1040 and SC1224 monitor today. Came home hooked everything up, all looked good. Played around in GEM for a few minutes and then just let the computer and monitor sit while still turned on. Came back into the room after about 30 minutes and immediately noticed something was wrong because I smelled the good ole circuit burning smell (and smoke from the monitor!). Turned the monitor off immediately and took the plastic cover off. Plugged it in quickly again to take a look and R707 was glowing red and smoking like crazy (damn that smell is awful!).

 

Where do I start? Or is this thing dead on arrival? My assumption is that it hasn't been turned on in years or decades and now boom!

 

Thanks guys!

Edited June 7, 2018 by Gunnder

[ParanoidLittleMan]

Well, I think that we will see more and more posts asking for help in case of computer or peripheral failure.

I'm not sure that one Atari forum is right place for remote servicing of monitors. And generally, what is it with people today ?

In 'my time' people brought it in service. Or repaired self without Internet .

 

Don't get me wrong, it is nice to help people, but this way is just bad. It seems that now time is too cheap.

People worked, earned money, so they did not waste time in something for what were not experts.

I could repair myself my wash machine, but why do it, when I have lot of job on my workplace - so I called repair man for wash machine, he fixed it 5x faster than I would, I paid it, and solved.

 

I think that should open new section in forum, dedicated to posts like this, of course computer errors too .... Will be more and more, for sure. Although, I'm not sure that admins will see this at all. ..

Just to add that I getting more and more game error reports - and in 80% there is no error with my game release. It's computer, PSU ...

[tjlazer]

The reason is easy to understand. It is 2018 and there are not Commodore or Atari service center nearby to drop it off to get looked at or get fixed. And shipping a monitor to someone to do is out of the question. Shipping a monitor in the US costs $75 or so and to ship it across the pond would cost a few hundred $. (not to mention the risk of damage) TV electronic shops are rare to find these days, so we are left with what we have. The Internet. Nothing wrong with asking the question to see what this component is, and if just replacing this burnt component will fix the monitor. What I don't understand is how people like you get annoyed and feel the need to complain like this?

Edited July 2, 2018 by tjlazer

[oky2000]

There might be some service manuals for it floating around the net which might help.

 

The components inside just can not last much longer in most real hardware from the 80s, I don't know if it matters if you use them constantly or hardly ever. Happens all the time, I bought a Commodore 128 once and powered it on for a quick check then left it switched on whilst I finished off something and it just crashed and never booted up again when I turned it off and back on. Sign of the times really.

 

I had a similar thing happen to my only SC1224 due to a faulty Mega STE, the fault being even when a colour monitor is connected it still tried to output the 70hz/32khz mono mode on the SC1224 and smoke started to come from the back and the 'lovely' smell of the magic blue smoke escaping I was lucky because I turned it off immediately. Monitor worked fine for years before I got that Mega STE from a car boot sale for 50 quid more than a decade ago.

[ParanoidLittleMan]

The reason is easy to understand. It is 2018 and there are not Commodore or Atari service center nearby to drop it off to get looked at or get fixed. And shipping a monitor to someone to do is out of the question. Shipping a monitor in the US costs $75 or so and to ship it across the pond would cost a few hundred $. (not to mention the risk of damage) TV electronic shops are rare to find these days, so we are left with what we have. The Internet. Nothing wrong with asking the question to see what this component is, and if just replacing this burnt component will fix the monitor. What I don't understand is how people like you get annoyed and feel the need to complain like this?

There were never Atari and Commodore services here, in middle Europe and wider. Myself repaired plenty of Commodore, Sinclair, Atari computers + monitors at time. As general service.

I'm not annoyed at all. Just that resistors never burn by self. What OP asked here is basically remote service help. I don't think that it belongs in some general computer forum. I saw here very long threads about some repair. Will it help other users ? Very little. Every fixing is different. As said, dedicated section for it would be best, With some longer sticky threads about basic things, what should be read before posting. Nothing special, nothing new. Just in purpose to make things more efficient.

I don't think that I mentioned anything like shipping monitor in service. And if there is no some service or some friend with experience in place, then better to forget thing. Actually, there is often shipping involved - you buy something in some shop, and they will take over fixing it if it happens. Not self will fix - they bring every non-trivial error to dedicated service for that product.

Btw. I read long time ago (30 years) about practice of US services with TV-s : you bring TV in service. They look first is there service manual for that model. If no, will not touch it until not getting that manual from manufacturer. It has justification in high price of employees. Here things were different, in most cases. There were and are some specialized ones, for most popular brands, but most is general. Service manual ? Not really needed.

And old way of repairing works not anymore, with new things. I guess that new generation of service people using soldering iron very rare. No practice with older electronic. That would be rather the problem, and not need for shipping.

[Gunnder]

Just an update on this. i tracked down the burnt resistor along with the burnt diode. Replaced both and monitor came back to life. Its been running for a few days now (few hrs a day) with no issue whatsoever. Pretty happy I was able to figure it out all by myself plus with the help of the schematics

[ParanoidLittleMan]

Good job.

I think that people should always do it: get schematic if possible. It is easy and usually free now thanx to Internet. In 80-es we needed to order it from some service or Atari (generally manufacturer) what took money and time.

 

Btw. usual problem with old devices are electrolyte capacitors. Especially if they were not turned on for longer time (years) . But of course everything gets weaker gradually.

[Gunnder]

Funny that you mention capacitors because I saw about 12 of them that had this brown stuff below them so I took them all out thinking that they leaked, tested them they're all fine and I put them all back in the same way. I realized it was brown glue to keep the capacitors in place. LOL I guess I really should replaced the ones I removed but I didn't have any on hand and I checked them all there were still all good so I just put them all back in.

Good job.

I think that people should always do it: get schematic if possible. It is easy and usually free now thanx to Internet. In 80-es we needed to order it from some service or Atari (generally manufacturer) what took money and time.

 

Btw. usual problem with old devices are electrolyte capacitors. Especially if they were not turned on for longer time (years) . But of course everything gets weaker gradually.

Edited November 30, 2018 by Gunnder

[ParanoidLittleMan]

Yes, typical for Chinese and generally Asian manufacturers that they added glue to secure larger/harder components. And Atari had factory in Taiwan.

Electrolyte capacitor leaking happens usually at top, when cover part, which is weakened opens a little.

Ah, and brown glue was not always brown, that's because age in many cases, since original color is rather yellow.