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About ST-ranger

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    Combat Commando

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  1. Yes, it definitely looks like the metal film one. Will get to ordering it straight away. For those that are counting, it has cost more than a modern industrial PSU replacement, but has been triple the fun.
  2. Thanks - I've only got the 1 ohm resistor in 0.5 W, will that do? Thanks also for the excellent video, learnt a lot. Took the diode out of circuit, it tests ~ 0.520 in forward bias and OL in reverse, so guess it's just fine.
  3. All parts arrived and have been busy fixing things up. R8 is also damaged on the bottom however the schematic lists it as: R8 1 Ohm Is this also a 0.5 W part? It looks much more comparable in size to R5 which is 51 Ohms & 2 W. Thanks again
  4. Great information, thanks again. Everything is ordered - will post progress! Cheers
  5. This is fantastic, thank you so much. I've ordered the SC1384 TO-90L from China - the wait is only a month or so, and they were incredibly cheap. Sadly I'll have 49 of these leftover, feels like a waste, perhaps time to do the other Ataris while at it. The W10M, have found a source over here - how do I tell if it's mains rated? Here is the blurb from "fleaBay": >"The 1.5 Amp Full Wave Bridge Rectifier (W10M) is a single phase Bridge Rectifier. Voltage Range is 50 to 1000 Volts and Current is 1.5 Amperes." Because my voltage range lies within this (220v to - 240v) is it safe to assume that it is mains rated? Thank you! All ordered. -edit- when choosing resistors, is the resistance non-negotiable & the power flexible, similar to capacitors? I.e. if I need a 51 ohm resistor at 2W, can I choose a 51 ohm resistor at 3W, or perhaps below at 0.6W? Which is better? Thanks.
  6. MasterMotorola, thanks for your quick reply, much appreciated. I've watched the video now, glad to know there is a drop-in replacement. They are readily available in Australia - can I use these to replace the supply in my 1040STfm and STe? If so, I might do that, and continue to repair the current one. I have been through the schematics - it looks as if it's in another language to me. Here are the values I've come up with for things that appear damaged: R5 - 51 ohms 2 W R4 - 330 ohms 2W R6 - 3.3K ohms, watts not specified R7 - 15 ohms, watts not specified C8 - 1 uF 16v Is it okay to use any wattage for the above without a W rating? I might be able to get these from the local electronics supplier. There are also two components which I'm totally stumped by: Q1 - ? SC1384 DB1 - No value - another part of the site shows it as a "bridge recitifier". On the original part is has printed on top: "G1 W10M 8741" Where could I source these components? There are specialty stores I've used for ZX Spectrums, Amigas, etc., however haven't found anything which sells these components for STs. Thanks again
  7. 'Morning all, Currently in the process of repairing a poorly 520STfm. This is a UK 520, and it has found itself in sunny Australia, where the voltage is the same (220-240v). Board is nice and clean, no issues with burst caps or any other visible damage. The main symptom has been no power. I am replacing the PSU caps based on the Techwiki Astec ASP34 (Mine is ASP34-2). After removing all of them, I note most of the PSU caps have leaked at some point, so I have cleaned up the bottom & top of the board. Please see the photos. One of them has explosively decompressed out the side ( C7 ) . A couple of components also look burnt and/or damaged. Could anyone please assist in identifying the components in the pictures so I can replace them? I have pointed to them the best my limited paint skills allow. Thanks in advance all.
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