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AuthorTopic: Someone can repair a 1084s monitor?  (Read 697 times)

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Offline efrenmgp

Someone can repair a 1084s monitor?
« on: May 08, 2021, 08:15:13 PM »
Hello all!

Well as the subject says. I have a 1084s monitor that stopped working a few years ago. A friend and I were playing and it just made a crack sound and that was it. Now that I am reviewing all my Amiga stuff, when turn it on it just makes kind of the same crack noise and nothing else.

I have limited skills with electronics. I know how to discharge it, I can replace parts, but I know absolutely nothing about how to diagnose the failure.

So, I am considering sending it to be repaired with someone with proper skill and knowledge. I know Indivision cards are great and I have one of them, but I really like the image on those monitors.

I have tried looking for someone here in Mexico but I can only find TV technicians who almost laugh at me when I tell them this is not a flat screen TV :(

So... I'm afraid the cost will be high or even prohibitive but it is worth asking anyway. Does anyone know someone who could do this job? Preferably in the US.

Thanks a lot!

Regards,
Efrén
 

Offline TribbleSmasher

Re: Someone can repair a 1084s monitor?
« Reply #1 on: May 08, 2021, 08:59:32 PM »
Sending a CRT via mail will increase the potential damage to it by a tenfold. Those monitors are heavy and not handled the way they deserve.
 

Offline Pat the Cat

Re: Someone can repair a 1084s monitor?
« Reply #2 on: May 08, 2021, 09:23:02 PM »
Dangerous to try repair yourself though. Cribbed this from justanswers.com

Quote
Still, the described symptom would almost always point to a high voltage arc. The snapping sound is produced by the high voltage sparking over an air gap.

...
Possible suspects are:

    • failing CRT / high voltage is jumping at the neck and/or at the rear PCB (least likely);
    • dampness / dust at the anode cap providing a spark patch for the high voltage to jump over (likely);
    • a crack in the FBT (flyback transformer) hence the high voltage is leaking out (most likely).


There are other places where high voltage can leak to earth and produce the sound.

What you really need is a technician who is competent with high voltage analog electrical repair. Keep asking, if they are happy with terms like "Line Output Transformer" and working close to thousands of volts, they can probably find exactly where the leak is.
"To recurse is human. To iterate, divine."

A1200, Vanilla, Surf Squirrel, SD Card, KS 3.0/3.z, PCMCIA dev
A500, Vanilla, A570, Rev 5, KS 1.2/1.3 Testbench system
Rasp Pi, UAE4ARM, 3D laser scanner, experimental, hoping for AmigaOS4Arm, based on Watterott Fabscan Pi
 

Offline efrenmgp

Re: Someone can repair a 1084s monitor?
« Reply #3 on: May 09, 2021, 02:22:10 AM »
Thank you very much for the answers :)

I'll search now in those high voltage terms, good advice!

I hope to find someone soon. If not local, at least at a reasonable driving distance.

Regards,
Efrén
 

Offline Plaz

Re: Someone can repair a 1084s monitor?
« Reply #4 on: May 09, 2021, 04:45:08 AM »
the cost will be high or even prohibitive

Yes.  :(

"Flyback transformer" failure was a common problem with certain versions of the 1084 and 1084s models.
But it's been a couple of decades since replacement flybacks were available.

Senario 1 ..the flyback leaks or shorts completely, which then kills other components in the high voltage section and the power supply.
The 1080's were work horses and also many of the earlier 1084's.
However in Commodore's last years I found the later model 1084 and 1084s to be very cheaply made with higher failure rates.
(and don't even get me started on their multisync 1950 and 1960's :P)


This is a quick test for a technician that might cost a $2 fuse.
With power removed, open the monitor and blowout ever bit of dust. Especially around and under the flyback and also the back of the tube.
Inspect the circuit board for any burns or very dark colors. If any damage is seen... abort.
If the circuit board looks clean, replace the fuse, re-assemble, and power up.
Three possible outcomes...
1 - Turns on (Yay! Until it goes out again some day)
2 - Pop! (bad and expensive components have blown the fuse again)
3 - Power button light flashes. (power supply and other components are probably ok, but the flyback has died)

If a repair is needed, it would be expensive and maybe not even possible due to lack of available parts.
I'd look at some of the other options available these days that have a better looking picture.

Plaz
(with thousands of monitors repaired in an alternate time line)



Offline Castellen

Re: Someone can repair a 1084s monitor?
« Reply #5 on: May 09, 2021, 09:01:56 PM »
I'd agree with the suggestions above from Plaz.

It is easy enough to source some 1084S parts.  4-5 years ago I replaced the failed line output transformer in my workshop test monitor with a new one from Ebay.  The monitor gets a lot of use and the replacement part is still working perfectly.  A quick note for anyone looking to replace a line output transformer, there's two main variants of the 1084S, you need to select the correct part:
https://www.ebay.com/itm/323271046225
https://www.ebay.com/itm/323881872931

The Commodore monitors are not significantly different to a CRT television, so providing you can find someone local familiar with repairing CRT TVs, then it's probably realistic to repair the 1084S.
 

Offline Plaz

Re: Someone can repair a 1084s monitor?
« Reply #6 on: May 09, 2021, 10:12:02 PM »
It is easy enough to source some 1084S parts.

Nice, the amazing world of "old stock" on ebay.

As Castellen mentions, make sure it's an exact number match.

Plaz
 

Offline efrenmgp

Re: Someone can repair a 1084s monitor?
« Reply #7 on: May 10, 2021, 04:53:08 AM »
Hello and thanks a lot!

Great! Good to know those parts are available. I think I can do the cleaning / visual inspection / fuse test. As long as I don't have to mess with it while it is both open and turned on  :o

Thanks again everyone!

Regards,
Efrén