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blown component on Sony MP-F75W

F

feltel

6502
I was renovating one of my Compact Macs floppy disk drive. Its gear broke in pieces. I took the chance to clean and grease it. Upon reconnect it i heard a short electrical crackling. I imeadiately shut down the machine. Upon inspecting i found an broken/chipped component on the disk drives PCB. Q4 does not look right. I dont know how this could happen. I held the drive in my hand and nothing was shortening. Anyway. Is there anyone who can tell me what component this? It would be a shame to throw away the drive due to a small component failing

PXL_20230712_054018426.MP.jpg
 
I can’t answer the question, but please don’t throw away the drive. I’m sure plenty of us have spare boards at a reasonable cost that you could use to replace the bad one, or would be willing to buy your broken drive.
 
Rest assured I wont throw away the drive at any time soon. :)

With the help of a picture search I could validate that the blown component is/was a transistor with a "BV5" marking. I'm currently checking suppliers for a suitable replacement component.
 
I did this once accidentally. I did find the part. Believe it or not this was something like three years ago…and I still haven’t replaced it! I do, however, have the parts and can tell you what it is if you can wait until I get home late this evening.
 
@LaPorta were you able to find out what the component was? I just came across a F75W with the same component blown. Looks to be a transistor but not sure which type.
 
It should be a "2SB624" which goes on Q4. I ordered a bunch of these on AliEx and hope to get this drive working again. While Q4 blew up I tested the drive without the eject motor in place. Could this be the root issue of blewing up Q4?
 
I have also blown this exact part, it connects to the eject mechanism. My guess is that something jammed the eject motor so that it used too much current (or that it was connected wrongly?). In my case, replacing it with the same part from a broken drive made it work perfectly fine again.
 
jmacz said:
@LaPorta were you able to find out what the component was? I just came across a F75W with the same component blown. Looks to be a transistor but not sure which type.
Click to expand...
Really sorry, I have had some family emergencies of late. I will see if I can nail it down tonight.
 
My drive did blew up components when "used" without the drive eject motor attached. 🧐
But this could be pure coincidence.
 
LaPorta said:
Thank you, things are going better. Yes, indeed, that was EXACTLY what I did as I now remember: tested the drive without the eject motor in place. Not only did I take out Q4, but Q9 and R48 as well. Q4 and Q9 are the same. Q4/Q9 are Zener Diodes, 3.0 Volt 0.3 watt.

Click to expand...
yeah Q4 is the high-side VCC switch for IC3. Whatever happened with IC3 blows Q4.

Q4 and Q9 are NOT zener diodes! They are transistors.

Q9 shorts CN3 1 and 3 together when enabled. R48 is a pullup to keep the transistor turned OFF when not asserted by the control circuitry.
 
I'm not that deep into electronics, at least at that level. Could you explain why Q4 blew up when the eject motor was not attached? It blew within a fraction of a second right after turning on the Mac. I could not even try to use the drive at all.

Why did Sony design it that way. Its not very fault "tolerant".
 
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