Sort of a tool. Electronics on the fritz.

[daveturnbull]

Like I said, sort of a tool. It helps keep me entertained whilst tinkering away in the workshop. Recently it's started playing up. It lives in a cold environment, and this seems to be key to the problem. When cold out, I'll turn it on and after a couple of clicks it shows 'OVERLOAD' on the display and shuts down. If I bring it in the warm house for a while, it works fine. I've also noticed that when it does fail, the display is dimmer than usual, which sort of points me to a power problem.

Of course, I've googled it, but that just throws up a load of issues with overheating (defo not the case here). Opening the case and on visual inspection nothing seems amiss. Caps all look good, no corrosion or burnt bits etc... The fan works as it should when you crank the volume up.

Focussing on the power board, all looks ok here too (to my relatively untrained eye).

Interestingly, after taking it apart to get these photos, I put it back together enough to plug in a test, and it worked. I don't know if that was because I had been handling it, or whatever connection is dodgy got wiggled. I'll try again later when it's colder outside.

So, for the electronics wizards on the forum, does anything in the photos jump out at you as being a potential suspect that needs a touch with the melty melty tool, or anything else?

[smallfry]

Dust used to be a problem with old "traditional component" electronics, even indoors. It would absorb a bit of moisture from the air, and cause semi shorting.

Condensation on a clean board will do the same. I remember our Radio Rentals repair man telling me all about this years ago, when he had come to look at our set. Again. Do TV repair men even exist now ?

Might be a component on its way out, but I would try lacquering the boards. Might help ?  

[sean f]

I am guessing if it is cold in the workshop it is also damp, this could be causing a partial short somewhere (possible in association with dust as above), not enough to cause a terminal escape of magic smoke but enough to cause it to shut down, having it in doors for a while might have dried it out enough to work.

We regularly have this issue with our offshore units, if they are shut down for several weeks or sometimes months the recommended procedure is to power them up with the blower and pressurisation on, turn on the heaters and leave them for 12 hours. Sometimes the client leaves things to the last minute to get us onboard and we have to rush this, on one job that meant I lost a Sparc station, PC, chart recorder, and terminal server to terminal bangs or pops (all going on the client bill) and only just had enough equipment left to start working, they still left it to the last minute again on the next job.

Assuming it is easily portable, might be worth keeping it in the house when not in use and seeing if it then works OK when taken back outside, if that works damp is probable the reason and either get something more robust, wait for warmer weather or store it inside when possible is the only solution I can see. If it has no effect then I am talking rubbish and just ignore me!.

[daveturnbull]

2 minutes ago, sean f said:

Sparc station

Blast from the past. I don't think I've seen one of them since about 1996!

After I took it apart to get the pictures and put it back together again, it has been largely behaving. The only connector that came apart was the transformer input (3 solid pins that slot into a connector on the power board). I think if it starts playing up again, I'll give them a squirt of contact cleaner to see if that helps.

[Peaklander]

Contact cleaner is 'magic' stuff. I have just sprayed the little pcb and wipers inside a CRV accelerator position sensor module. There were no signs of dirt but it has cured the engine codes that suddenly started appearing.

Edit: Having said that, I also sprayed the connector halves and they could just as easily have been the problem.

Edited January 27, 2022 by Peaklander

[Ed Poore]

Once you've got it working and dried it out thoroughly take out the circuit boards (but cover the connectors or anything that needs electrical contact) and spray it with a good conformal coating. Moisture issues go away then.

This is the one we use for our circuit boards and has been very good for what we've put them through - you can just about solder through it if you need to effect a repair in the future.

https://uk.rs-online.com/web/p/electronics-varnishes/1368533