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mitchW

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  1. I would also go and replace capacitor C15 in some near future. But use a different one, use a foil style cap 3.9uF 100V. It is described on page 159-160 of the Larry Pina's book The Dead Mac Scrolls.
  2. Just a quick question, I have an SE/30 that I think has a tube on its weak side. Can anyone confirm that? The focus is not as sharp, also I can make edges quite sharp, but the center will be bit soft and vice versa. Also I noticed that the top and bottom corners are bowed a bit in, hard to describe, but it looks like a geometry problem, however if I max the brightness, the thing worsens, also if I drop the brightness down a lot, it looks almost perfect. Should I look for a problem on analog board? I highly doubt it however, as it was doing the exact same
  3. Hi, I just fixed one Lisa 2/5 that had screen jumping vertically. The jumping became worse as the machine warmed up. Main culprits were three electrolytic capacitors on the analog board that have leaked and corroded the surrounding areas. These are three 16V 10uF capacitors that were purple in my case and of a unknown manufacturer. When desoldering there was a similar smell as when recapping later Macs (for instance SE/30, etc.). I used 25V 10uF caps, and I also cleaned most of the green corrosion around them. I have also replaced all the potentiometers as the
  4. I just repaired (recapped and cleaned the PCB) a PowerBook 170 Power Adapter M5140Z (APS-20E). Needed all of the brown ELNA capacitor replaced. 47uF 50V, 82uF 16V, 180uF 16V and 1200uF 16V were all leaking in the bottom. I was lucky as the corrosion around the caps was still minimal, so I didn't need to repair any traces. I replaced them with 100uF 16V and 220uF 16V Polymer capacitors and the 1200uF 16V with a Rubycon ZL series (Low ESR) one. For the 47uF 50V I just used off the shelf normal cap. Few other caps were fine, so I left them in. PCB was clea
  5. There was one capacitor on LC III models that was installed backwards from the factory. If you used ceramic capacitors, it wont matter, however if you used tantalum that capacitor may go eventually in smoke. See this thread: https://68kmla.org/forums/index.php?/topic/19752-lciii-recap-apple-design-fault-47uf-reversed/ Also wash the board and check your work. Also clean all the SIMMs.
  6. These Mitsubishi drives are very reliable, even with old capacitors in place, however do replace the capacitors, even if you do not see any leakage. Most of the drives had no signs of leakage around the capacitors, but when removed, there was almost always a small pool of electrolyte underneath it. In past, I repaired several dozens of Mac and PC floppy drives and most of the times there are problems with dust and dirty heads, but more commonly in last few years, there are problems with mechanical parts seizing up, even on "later" drives. I even managed to repair an 400K drive with a missi
  7. Huh, no replies? Well, I am still on a lookup for a suitable logic board for my PB G4.
  8. Probably the suicide fuse is blow, it can be replaced with a suitable thin wire. Located on the main battery PCB. 3 pin device. Had this happen on two occasions.
  9. I recently acquired a near mint condition PB G4 A1052 17 inch. The computer was from a friend of mine and it ran fine until about 4 years ago, then it started to show problems with GPU, artefacts, random lines and so. Not long after, it completely died. I know for sure that the LCD was good and all other components worked, even the battery isn't that old. I inspected it and the logic board is toast and beyond economical repair. For anyone interested, it has a shorted ATI 9600 M GPU chip, that is unobtanium these days (I was actually interested in replacing the BGA chip itself). Even after
  10. I am thinking of 3D printing a battery pack that would contain 5 AA cell holders that would be accessible from the outside, so one could be able to use the cells they wish and change them on the fly. I think you could be also able to use alkaline batteries (include a switch for alkaline use that would put the pack in series with a diode, so you won't be able to charge them). I use my PowerBooks quite rarely and when I get to use it, the battery is almost always flat, so I need to charge it for few hours etc. But I keep 8 AA Eneloop cells always charged, so I would just put them in. Als
  11. That would be the part to order: http://eu.mouser.com/ProductDetail/Littelfuse/1206SFS500F-32-2/?qs=sGAEpiMZZMsIz3CjQ1xegdajYV%252bSgOyhtRV3I06tmz0%3d
  12. I tore apart my parts Pismo and found a similar fuse there. It was located on charger board. This one is 5A and has Fairchild logo on it and also a "T" which means "Time Delay" or Slow-Blow. Replaced it with the one from Pismo and now it works. While I was there, I also measured 35V 100uF capacitor next to the fuse and sure enough, it had high ESR (about 0.6 ohms), so I replaced it with new one (ESR about 0.1 ohms). I think that in a matter of 5-10 years, all these iBooks and PowerBooks G3 might need capacitors replaced. Well, tear the thing apart and check continuity of t
  13. I am repairing a iBook G3 Clamshell that has blown fuse on the charger board (F1). This causes the known good battery not to charge, despite the orange light on the charger. Can anyone suggest what is the original specification of the fuse? It has "5" written on it. Considering my electronic knowledge, that would be 5A 32V Slow Blow? Thanks!
  14. I would leave ceramic and plastic film capacitors alone for now. Except if these are actually paper caps you are referring to. You probably saw cracks in clear case capacitors near the AC input on 128k/512k analog boards. These are plain old paper (or paper in oil) capacitors (usually from company WIMA). They are placed across the line and from line and from neutral to ground. When new, these capacitors were one of the best for these type of applications, as the paper has excellent dielectric properties and has very low dissipation factor. However, after 20-30 years the paper will slowly b
  15. It works!! I got the charger today, it looks reasonably built, but still feather light compared to original one. It measures 7.80V at the output with no load. At first when I tried it, the barrel did not fit completely into the back of the plug, the insulating sleeve was too long. I then used x-acto to cut about 3 mm of the plastic sleeve off, and now it fits. The PB 140 then started up with ease. So I guess we now have a source of cheap aftermarket PB AC adapters.
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