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ChrisCwmbran
July 14th, 2012, 10:10 AM
At the same time I picked up my Pet 8032-SK, I picked up the Phillips P2000C.

Did my usual visual inspection of the innards looking for obvious bad things i.e. burst caps, bad corrosion etc, but all looked fine.

Turned it on, and there was a bang and smoke poured from the side of the machine where the PSU is. No big deal. Looking through the grills on the side I can see two Rifa X2 capacitors one of which is "puffed up" significantly, and another which has significant cracking running along it. I'm guessing there is a third one, but I couldn't see it without taking the PSU board out.

When the machine is on, the screen displays a flashing block cursor, and the rest of the screen is filled with Xs. Searching around on the web it appears that this machine should have a blank screen with a flashing cursor until it displays its "CP/M version 2.2" message or whatever. Am I right to assume that this is an issue with a RAM chip, and the fact that the characters are formed nicely, suggests that it is one of the main RAM chips that is defective or I guess if it's in a socket, needs reseating?

The other problem I have is it seems with these machines that the carrying strap is what is used to clip the keyboard into place when it isn't being used. Does anyone have a spare strap? Or could they take photos and measurements so I can have one with whatever "keys" are required made up.

Thanks in advance.

WMH
July 14th, 2012, 04:17 PM
At the same time I picked up my Pet 8032-SK, I picked up the Phillips P2000C.

Did my usual visual inspection of the innards looking for obvious bad things i.e. burst caps, bad corrosion etc, but all looked fine.

Turned it on, and there was a bang and smoke poured from the side of the machine where the PSU is. No big deal. Looking through the grills on the side I can see two Rifa X2 capacitors one of which is "puffed up" significantly, and another which has significant cracking running along it. I'm guessing there is a third one, but I couldn't see it without taking the PSU board out.

When the machine is on, the screen displays a flashing block cursor, and the rest of the screen is filled with Xs. Searching around on the web it appears that this machine should have a blank screen with a flashing cursor until it displays its "CP/M version 2.2" message or whatever. Am I right to assume that this is an issue with a RAM chip, and the fact that the characters are formed nicely, suggests that it is one of the main RAM chips that is defective or I guess if it's in a socket, needs reseating?

The other problem I have is it seems with these machines that the carrying strap is what is used to clip the keyboard into place when it isn't being used. Does anyone have a spare strap? Or could they take photos and measurements so I can have one with whatever "keys" are required made up.

Thanks in advance.

Don't know much about CP/M machines myself, but I believe it's safe to say that you've got RAM problems.

From my limited experience with vintage equipment, it seems that garbage on the screen is almost always caused by RAM, so you've probably made a good assumption. If the RAM chips can be reseated, go ahead and do so. I don't think that'll hurt anything.

I'm also assuming you know how to replace damaged caps from all the machines you've been working on lately, so that's probably not a problem.

About the blinking cursor, you are booting with a system disk hooked up, correct? I know it seems like an obvious question, but I make obvious mistakes all the time, so that's always my first assumption.

leeb
July 14th, 2012, 09:02 PM
I was going to say...

Since it is filled with 'X' (or 'x') perhaps that keyboard key is stuck/shorted...

Unless it has built-in CP/M and/or an internal hard drive, it would be unlikely that it would come up to "CP/M " without assistance...
Or, perhaps it already did, and the keyboard buffer is full of 'X's...

MANY possibilities.
so little time! :p

WMH
July 15th, 2012, 05:18 AM
I was going to say...

Since it is filled with 'X' (or 'x') perhaps that keyboard key is stuck/shorted...

Unless it has built-in CP/M and/or an internal hard drive, it would be unlikely that it would come up to "CP/M " without assistance...
Or, perhaps it already did, and the keyboard buffer is full of 'X's...

MANY possibilities.
so little time! :p

True, hadn't though of the X key. But the fact that is was instantly filled with X's made me think RAM, because if the key were stuck you would see the screen fill up with characters. But maybe it takes the screen a while to warm up, or as you said, the keyboard buffer is full. But if the keyboard buffer was already full, that would be RAM, correct?

As you said, there are a TON of possibilities...

leeb
July 15th, 2012, 09:06 PM
True, hadn't though of the X key. But the fact that is was instantly filled with X's made me think RAM, because if the key were stuck you would see the screen fill up with characters. But maybe it takes the screen a while to warm up, or as you said, the keyboard buffer is full. But if the keyboard buffer was already full, that would be RAM, correct?

As you said, there are a TON of possibilities...

... and I took off of what YOU said... about 'random'.
RAM errors would DEFINATELY show up as 'random' characters... NOT a succession of 'X's... especially right after being shut off/turned on.
Now, if some sort of 'ram test' is running FIRST and is supposed to be CLEARING it but 'X' is showing up instead, THAT could be a RAM issue... tho I dont know off-the-top what ASCII for 'X' is... :rolleyes:

:)

(something started running in the back of my head...)
'Oh, the Apple and the Tandy should be friends...'
'Oh, the Apple and the Tandy should be friends...'
'The Apples think THEY do it right,'
'The Tandys like to take a byte,'
'And that is why the two should be good friends!'

... /hijack
:p

EDIT:
I wonder if the power could be 'dirty' enuf now to cause a pattern to be injected into the data? One wouldnt think so...

Chuck(G)
July 15th, 2012, 09:57 PM
Okay, I need clarification. You don't see a "CP/M" message, just a screen full of "X", right?

That could be a boot ROM issue or other memory error.

ChrisCwmbran
July 16th, 2012, 01:43 AM
Thanks for all your replies.

Thats right Chuck. All I've been able to do is a power on test. I know there is no screen display before the CP/M message from watching YouTube videos.

I won't have a CP/M boot disk for it until later in the week.

I didn't notice if it attempted to read from a floppy drive or not. Whilst I'm trying to find a time to replace the blown RIFA X2 caps, is there any harm to turning it on again to see?

ChrisCwmbran
July 20th, 2012, 05:20 AM
Right I've replaced the three blown capacitors - all burst as expected.

PSU refitted.

I get a screen full of # now and a steady cursor in the top left position.

It isn't a stuck key - it happens whether the keyboard is connected or not.

There is no attempt to access a floppy whether there is a disk in the drive or not.

The Caps Lock light on the keyboard doesnt appear to work at this time either.

ChrisCwmbran
July 20th, 2012, 05:57 AM
As an additional comment, when left powered on for approximately 10 minutes the screen change from:

9710

to:

9711

Pressing the reset button causes it to immediately return to the #s.

carlsson
July 20th, 2012, 01:25 PM
How is the latter screen even possible? I've got a working (it was last time I used it) Philips 2000c with some user documentation, if it can help you in any way.

tingo
July 23rd, 2012, 06:11 AM
Some component overheating? A voltage controller perhaps? Or the video circuit itself?

WMH
July 23rd, 2012, 01:24 PM
So, ChrisCwmbran, how's it coming? Any progress?

ChrisCwmbran
July 23rd, 2012, 01:29 PM
At the moment I don't have any specific ideas what to check in this case.

I'm hoping someone on here will come up with some specific suggestions as to what to try.

WMH
July 23rd, 2012, 01:45 PM
At the moment I don't have any specific ideas what to check in this case.

I'm hoping someone on here will come up with some specific suggestions as to what to try.

Sorry, I can't give any advice. I can wish you good luck. :)

Chuck(G)
July 23rd, 2012, 02:58 PM
The service manual is here (http://electrickery.xs4all.nl/comp/p2000c/doc/P2000C-SystemRefServiceManual.pdf) in case you don't already have it. It's quite good in its explanations. Note that there's the CPU board and then the terminal board, each with its own CPU and memory You can check out the terminal board section separately from the CPU as the interface between the two is simply a serial link. I'd probably start there.

listerdiesel
February 21st, 2013, 01:27 PM
We've got two or three of these at the factory, there are various options, including an add-on RAM board, Co-Power board with an MS-DOS facility if you have the disks to boot from CP/M into it. Ran an 8088 CPU at 5mHz.

The drives are 96tpi but write 360K double-sided MS-DOS when running on the expansion board.

The PSU's were bought-in by memory, I have one with a failed PSU that I swapped to get a couple of women running on their project.

Our two both have the expansion boards, we also have full electronic and software manuals, the big ones, not the small ones:

System Reference & Service Manual (Full schematics and PCB components layouts. 5103 993 30424
CP/M Reference Manual (Digital Research) 5103 993 11921

The GP300 printers that went with these were pretty substantial, RS232 mainly with selectable fonts and an 18-needle print head. We also have one of the 4000 series Word processors which we have had running with the GP printers.

The P2000C's were decent little computers, but quickly outpaced bu the MS-DOS world. Compared with the Osbornes, the Philips were far better engineered and built, but Philips weren't in a position to chase the rest of the world and dropped the PC side of things.

We also have, up in the loft, a Philips Videowriter :cool:

The two big manuals are under my desk, so can answer queries if anyone has them, but the 4000 series stuff is buried for now.

We do have full disk sets for the P2000C, CP/M, Wordstar, Calcstar, a graphics programme that I can't remember and a programme to address bulk letters from a database, another Wordstar product whose name I can't remember...

Hold on: Wordstar, Datastar, Mailmerge, Calcstar, Supersort, Wordmaster, Reportstar. Micropro was the software company that produced that lot, all on floppies.

That should keep you busy for an hour or so!

I'll look out the small P200C book.

Peter

listerdiesel
February 21st, 2013, 01:36 PM
My Service Manual is slightly more modern than the PDF, but it is only small details, I can't see anything missing that would be a big problem. We had updates from Philips regularly up to when they stopped support.

Peter