ASP34-2 - Looking a bit burnt

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Icky
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ASP34-2 - Looking a bit burnt

Post by Icky » Sat Nov 17, 2018 8:50 pm

Popped open my STE to recap the PSU and got drawn to the large metal film resistor in the centre of the PSU. The resistor and pcb area looks a bit burnt.

Although the PSU is operating I may do the same as the SR98 and replace the metal film resistors.

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Maeke
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Re: ASP34-2 - Looking a bit burnt

Post by Maeke » Sat Nov 17, 2018 8:54 pm

clearly the resistor heated a little bit too much, you should check it.
If i take too long to reply, sorry my cat is sleeping on my laps.

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Re: ASP34-2 - Looking a bit burnt

Post by PaulJ » Sat Nov 17, 2018 9:01 pm

Icky wrote:
Sat Nov 17, 2018 8:50 pm
Popped open my STE to recap the PSU and got drawn to the large metal film resistor in the centre of the PSU. The resistor and pcb area looks a bit burnt.

Although the PSU is operating I may do the same as the SR98 and replace the metal film resistors.


IMG_3293 (1).png
Icky not to worry.. think it has resister envy.. It wants new resisters just like the other supply. :) :) :)

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Icky
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Re: ASP34-2 - Looking a bit burnt

Post by Icky » Sat Nov 17, 2018 9:08 pm

Maeke wrote:
Sat Nov 17, 2018 8:54 pm
clearly the resistor heated a little bit too much, you should check it.
Absolutely - I intend to replace it.

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Icky
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Re: ASP34-2 - Looking a bit burnt

Post by Icky » Sat Nov 17, 2018 9:09 pm

PaulJ wrote:
Sat Nov 17, 2018 9:01 pm
Icky not to worry.. think it has resister envy.. It wants new resisters just like the other supply. :) :) :)
I know. I think it saw the other one and thought how do I get new resistors.

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PhilC
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Re: ASP34-2 - Looking a bit burnt

Post by PhilC » Sat Nov 17, 2018 9:09 pm

Jeff's revenge.

Got to do an ASP34 myself soon, not quite so sunburnt though.
If it ain't broke, test it to Destruction.

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Re: ASP34-2 - Looking a bit burnt

Post by rubber_jonnie » Sun Nov 18, 2018 9:16 am

I smell magic smoke....

How does the underside look from a heat perspective? Hopfully the tracks are undamaged and you can just replace the parts.
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Re: ASP34-2 - Looking a bit burnt

Post by exxos » Sun Nov 18, 2018 11:08 am

Looks like that psu must have been running a really really long time to get in that state. Its not that uncommon to see things like that. The resistors just get so got over time they start to burn, and burn the PCB as well. The resistor could actually be fine still, though always best to change parts which look burnt anyway.
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Re: ASP34-2 - Looking a bit burnt

Post by Icky » Sun Nov 18, 2018 3:08 pm

rubber_jonnie wrote:
Sun Nov 18, 2018 9:16 am
I smell magic smoke....

How does the underside look from a heat perspective? Hopfully the tracks are undamaged and you can just replace the parts.
Not so bad underneath. A bit scorched but tracks are intact. Looking at the side of the transformer next to the resistor that is a bit scorched too.

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Re: ASP34-2 - Looking a bit burnt

Post by rubber_jonnie » Sun Nov 18, 2018 5:06 pm

Looks like it's been left running for long periods, my only concern would be that the phenolic PCB could break down and fail and take the tracks with it, as under heat it can go that way. I have seen a lot worse though! (My Uncle was a TV repairman back in the days of valves and CRTs, and phenolic PCBs were quite common)
Collector of old Atari things:
800XL + Ape Warp mod, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg) + Gotek, 1040STFM + Vortex ATOnce + Gotek, 1040STF long button floppy, 4160 STE with Gotek and ROM switcher, 4160STE with 32Mhz booster, ROM switcher and CosmosEx, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

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