Raoul Duke's Gonzo Adventures

[raoulduke]

Sorry... I have to be a tool like everyone else.  (Follow-up... sorry everyone else).

As I was careening through the streets this morning in a rented convertible Cadillac, I came upon an outwardly pristine LC with a pretty good condition 12" RGB monitor.  As best I can tell the monitor works fine; I haven't actually tried it with a working mac.

The LC was open (beautiful day; no rain) but its PSU connector was disconnected.  I wasn't surprised when there were no signs of electrical life.  So how do I replace the PSU?  Alternatively I might part out the LC.  I didn't really expect to find it and I've never been a huge fan of LCs.  Conversely, I have no other 68020 machines.

 

[CompuNurd]

The PSU connector is disconnected? Do you mean that the physical connector that goes into the motherboard has become detached/broken off of the PSU?

 

[raoulduke]

No, someone (clearly) had disconnected it; nothing is broken.  The 80SC drive is in there (I may test it later); otherwise the floppy drive is missing its door.  Everything else looks really nice.  I just checked eBay and I'm not in a hurry to pay at least $30 to replace the PSU.

There was also a PRAM battery (oddly from 96, so someone probably changed it; the machine is liberally internally labeled 1990).  I'm assuming there would be some sign of life even with a bad PRAM battery?  (Idk if the LC needs a PRAM battery to boot - so far none of my models have so I'm not familiar with those that do/may.)

 

[raoulduke]

Obviously (I would guess to anyone who knows LCs) it's not a PRAM battery issue.

 

[Elfen]

The LC does not need a PRAM Battery to Boot.

The PSU, unless one of the transformers blown, can be fixed with a Recap. But the LC will need a Recap too.

 

[raoulduke]

Well I was thinking about recapping it (almost regardless of whether I keep it - it's good practice and I am increasingly unsure I can fix my SE/30's C12 pads).  But yea I just wanted to turn it on first.  If it's just a cap issue (and there are no obvious signs of physical damage - blackness/charring etc.), would there potentially be no signs of life?  When I flip the power switch in the back and try a soft boot from the keyboard I get nothing at all.

 

[raoulduke]

(If it's just a cap issue with the PSU I meant - sorry)

 

[CompuNurd]

With an LC, to boot just flip the switch on the PSU. If you listen closely, you should hear "tick tick tick" which means you need a recap. I have the capacitors you need to do an entire recap for $10 shipped. This assumes you have a TDK PSU, I don't have capacitors for anything else.

 

[raoulduke]

Yes.  There is a low clicking I didn't hear the first couple times.  Good.  However, a closer look at the logic board reveals it definitely needs to be totally recapped... I may have some of the P1 caps it uses, but I don't know if this is worth it to me - to spend like $20/30 even if it does work in the end.  It is TDK.  I'll get back to you on the recap kit.  Maybe toward the end of the summer.

I was watching a youtube video of an LC PSU recap after which the guy hit the PSU with a hairdryer to apparently help with the caps he had not replaced.  I guess any chance that might help?  (I'm guessing not - I did unplug everything I could think of (HD, floppy, fan/speaker - and RAM and ROM why not...) but that didn't affect anything.

Pics in 1 sec... (10% Complete!)

 

[CompuNurd]

Sometimes the clicking is hard to hear. I have had to put my ear right against some units just to hear it faintly. Also a word of caution: when you open these things, the line filter capacitor remains charged with lethal voltages. You want to carefully (with one hand in your pocket) remove the board and short the two large contacts near the middle of the board with a screwdriver. I have done this often, and sometimes it produces a spark, but that confirms the short was successful. I would touch the leads with a screwdriver a few times to make sure. If you wait half an hour, most of the voltage should have drained and you shouldn't have a problem, but I still short it to be safe.

 

[raoulduke]

It sounds similar to CRT caps discharge but I don't see what you mean on the lobo, so I assume you must mean the PSU?  (otherwise after the last 10 minutes I'm very lucky to be alive lol).

The one working thing (honestly I'm more glad I got the monitor than the LC - I threw one out about 15 years ago... regretted that until yesterday):

Sorry for the blur and perennial rotation.  The closeup of the board should show what I mean about the gunk or whatever it is.

Actually... should I clean the board first?  That isn't to say I won't clean it anyway, but is it possible that 1) a cleaning and(/or?) recap will have some impact; 2) can I turn the power supply on disconnected from the mobo?  I've asked this about my Compaq, but can I see if it works at all?  Can't clicking also be a symptom of mobo failure ('we' have talked about this re: the PB 3400c - obviously very different architecture though)?

 

[CompuNurd]

I am talking about the PSU as far as recapping and discharging capacitors. On an LC you need the PSU and LB recapped. And no, the PSU cannot, as far as I am aware, be operated outside of the LC.

 

[raoulduke]

Pretty good get on the monitor, I think.  The HD didn't mount automatically which I've never seen, but did with SCSIProbe.  It wouldn't boot the machine and I'm not set up for a SCSI-to-SCSI transfer right now but I will save the contents - probably via Kanga.

 

[bibilit]

the PSU cannot, as far as I am aware, be operated outside of the LC.

Yes, you can, as far as i can remember you should find two black wires for ground (on the left) rest are + 5v / +12v / -5v 

Never tried myself, but probably a way to use a modern PSU (PC one) just for a test.

otherwise the floppy drive is missing its door.

The floppy drive has no door on the LC (except if it was change for the manual inject type)

I didn't really expect to find it and I've never been a huge fan of LCs

I wasn't either, but are easy to work at and useful to make floppy discs copies...

You probably can clean the board with a contact cleaner first.

 

[raoulduke]

Thanks very much.  I'll look into the PSU thing, because I have to test another PSU as well.  I'll definitely clean the board, but I increasingly suspect that the PSU failed very recently and that the LC's owner was knowledgeable enough to know that.  So I suspect as old and dirty as the board is that the PSU is probably the operative problem.

 

[raoulduke]

Any thoughts...?  PC Creations PCC-5-10L.  I tried to take a photo of the connector (there's no other interface that I can see) because it looks like some sort of disk controller - 14-pins.  Dated July 8, 1985.  PC Creations was a Detroit company started in 1985 so this was likely a flagship product.  However, I have no idea what it's for.  I also found a TRS-80 Deluxe Joystick, which I will try to figure out if I can use somewhere.

 

[raoulduke]

Lol... it's a hot tub control board... maybe I should send that guy a message. Maybe my model's compatible with his. http://www.rhtubs.com/cgi-bin/bbs/config3.pl?md=read;id=22784

 

[raoulduke]

Can I use my Apple RGB Monitor on my PM 7100?  Wiki says it was made for the IIgs (which I had not known) but could be used on Mac II.  Obviously I can use it on the PM 7100 in the sense that it displays properly.  Is it going to do any harm to the machine/monitor (or just, for instance, unnecessarily - as far as the machine is concerned - limit the resolution/colors)?

 

[Compgeke]

It'll work fine, the 15-pin Apple monitors are all compatible with what Apple shipped. A few exceptions would probably be something like a Radius GS/C(M) cards which are fixed res 1152x882, something a 7100 wouldn't have.