Jump to content
Have You Played Atari Today?
2600|5200|7800|Lynx|Jaguar|Forums|Store

ST-ranger

New Members
 View Profile  See their activity

  • Posts

    21

  • Joined

  • Last visited

 Content Type 

Everything posted by ST-ranger

  1. ST-ranger
    Thanks. Ended up putting in a 10uF 50v. Upon boot now, the HDD sounds healthy and am less worried about tantalum-related issues. However, I can't remember - does one require HDX Utils disk to be in the drive? The HDD doesn't mount on the desktop. Downloaded the hdx504 disk but it doesn't contain any autoboot folders or anything.
  2. ST-ranger
    Thank you! I was looking at the C27 above it. How many Volts should it be? 106 = 10uF 6v? 16v?
  3. ST-ranger
    Thanks! Should have quoted it - the value on the side simply says "106L" or "I06L". Is this enough to positively identify it? How curious with the circuit diagram. On the motherboard is printed: SH205 C100169 REV.5 Reading up, it looks as if this is the 20MB circuit board. Found the schematic for it, which in fact has a C27, but can't really read it (55uf???): https://ia600206.us.archive.org/26/items/Atari_SH205_Schematic_1987/Atari_SH205_Schematic_1987.pdf
  4. ST-ranger
    Forgot to mention - it's a Megafile 30. Have looked all through the schematics here: https://ia800203.us.archive.org/2/items/Atari_Megafile_30_60_Service_Manual_RLL_undated/Atari_Megafile_30__60_Service_Manual_RLL_undated.pdf And unable to find a C27.
  5. ST-ranger
    Greetings all. Cleaning out my Megafile (dust & etc. build-up for years!) and noticed a glaring Tantalum in the upper left corner. Have had terrible times with these in old PCs so figured I'd replace it. Only problem is - what is the value? Is this the only Tantalum one has to pay attention to in the drive? Thanks
  6. ST-ranger
    Thanks, this is great information. The "parallel two caps for the correct value" part was a little confusing. I'll take the display apart and see if I can find this section. Hoping you're right, I will definitely attempt a recap. Understand the feeling completely not being able to test things... sometimes it's not really practical or acceptable in a social sense. Sadly, it reduces my enthusiasm from buying from "that guy who always acquires cool stuff for nothing!". Unfortunately, there is no power light on the SC1224... just an oscillating electric-style buzz. I will take them both apart, discharge them (hopefully can find the ground lug) and see what they look like inside.
  7. ST-ranger
    Thanks, these are helpful. I'm becoming comfortable with discharging and recapping CRTs now, however these manuals are practically hieroglyphic. Have read little scare bits-n-pieces about creating x-rays with poorly aligned tubes, so confidence is low that I'll be repairing them myself. This probably would have been the sensible move. Unfortunately I got ahead of myself there, had previously picked up quite a fair few 80s computer items from him that were perfectly repairable for great prices. I "trusted" that they were an easy repair. He definitely wasn't inexperienced with electronics (house covered in gaming consoles from the '90s), however not sure about CRTs. Lesson sorely learnt for a few hundred $AUD. Hoping you're right. Would also like to hold onto them and enjoy Lemmings etc. in colour. The condition is good to very good, sadly. No scratching, blemishing, or yellowing. The screens look immaculate. Thanks for your help
  8. ST-ranger
    Just today picked up an SC1224 & SM124 for prices slightly lower than market, to go with the 1040 & STE. Turning them on, feels like I fell for the "just need a recap" line. Was unable to test them at the guy's house. SM124 - Screen rolls vertically, slowing down until it stops with the screen bottom halfway in the middle and horizontal white lines. SC1224 - no power light. High-pitched buzz that oscillates in frequency, unaffected by contrast etc. knobs. Have I got lemons?
  9. ST-ranger
    Yes, my bad. Doesn't measure any resistance. Neither R19 nor R9 do. Others have been taken out of circuit and appear OK. Both have been taken out in the photo, (R19 laid beside) R19 on its own:
  10. ST-ranger
    Alright, everything has arrived & is fitted. One more piece of the puzzle to go - noticed an "R19" resistor that isn't present in the schematic at all. It's one of the smaller ones. This doesn't measure any capacitance when taken out so it must be replaced too... have looked at all the different revisions of the schematic apart from my ASP34-2 and it doesn't appear present, they all go up to R18 (this is the one in line with the power connection to board). Which value would be best here?
  11. ST-ranger
    Thank you. Results of tests: Meter on 200 ohm range red lead to pin 1, black to pin 2 = rapidly drops from 1.2 to 0.3 and stays red lead to pin 1, black to pin 3 = rapidly drops from 1.2 to 0.5 and stays Black lead to pin 1, red to pin 2 = rapidly drops from 1.2 to 0.3 and stays Black lead to pin 1, red to pin 3 = rapidly drops from 1.2 to 0.5 and stays If I use the lowest ohm setting (black right arrow with horizontal line through and vertical line intersecting the end of the triangle - pressing "func" changes it from continuity to this mode) All tests above read 0.002 Does this indicate replacement required? The spec sheet was exremely helpful. Found some "BU508A POWER TRANSISTORS(5A,1500V,125W)". Sounds like they would be a perfect fit. Thanks
  12. ST-ranger
    I have just done this, as suggested. (-edit- tested removed from PSU) Following this guide: https://www.wikihow.com/Test-a-Transistor I tried the black probe on the end leg, and red on middle and opposite. All beep & read 000.7. Swapped these around, red on end leg, black on middle then opposite. All readings 000.7 & constant beep. Tried with one on middle then opposite probe on one leg then another, same as above. Looking at this datasheet : https://pdf1.alldatasheet.com/datasheet-pdf/view/22038/STMICROELECTRONICS/BU508A.html It seems I should have at least picked up on the correct combination to test it. Does it sound fried? I have looked at replacement transistors and the only reasonably priced ones are in the TO-3P and TO-247 packages. Is it necessary to get the TO-218? Thanks again
  13. ST-ranger
    Thanks! Q2 is the big one wrapped in the rubber blanket... stripped it down, looks just fine. There is also a "Q3" which also looks fine. Can't see any other components that look damaged in any way, apart from the recently blown resistors. Is there another test I can do? Or, time to throw in the towel and get a modern PSU?
  14. ST-ranger
    Well, that was eventful! After replacing everything, plugged it in, turned it on... "BANG!" Double blue flash. Looks like the new fuse is cooked, along with the R8 & R5 resistors. R8 was replaced with a 1 Ohm 2 W part. R5 was replaced with a 51 Ohm 2 W part. Totally stumped now. Poor quality resistors? Some other problem? Thanks all.
  15. ST-ranger
    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.
  16. ST-ranger
    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.
  17. ST-ranger
    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
  18. ST-ranger
    Great information, thanks again. Everything is ordered - will post progress! Cheers
  19. ST-ranger
    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.
  20. ST-ranger
    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
  21. ST-ranger
    '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.
AtariAge
Forums
Store
General
Follow AtariAge

Copyright ©1998-2023 AtariAge

×
×
  • Create New...