View Profile: dave_m - Vintage Computer Forum

Yesterday, 09:28 PM

dave_m replied to a thread PET 2001 Issues in Commodore

What is the dash number of the kernel ROM D9? Is it 901465-03 (BASIC2) or 901465-22 (BASIC4)? Somehow the PET has got itself into the machine...

7 replies | 58 view(s)

January 23rd, 2020, 09:53 AM

dave_m replied to a thread Commodore CBM 2001-16N - BIG MESS! in Commodore

I found a picture of the Grundig SO100 and it looks like a nice digital scope. The vertical channel controls look conventional, but the horizontal...

13 replies | 301 view(s)

January 22nd, 2020, 02:50 PM

dave_m replied to a thread Commodore CBM 2001-16N - BIG MESS! in Commodore

I totally agree. For an old 1 MHZ computer like the PET, a used analog scope of 100 MHZ bandwidth is all you need. I like the Tektronix 454 or 465 as...

13 replies | 301 view(s)

January 22nd, 2020, 09:11 AM

dave_m replied to a thread Commodore CBM 2001-16N - BIG MESS! in Commodore

The PET has a lot of small bipolar TTL and the 40 pin chips are NMOS. It would be better to use TTL rather than CMOS. There should be pulsing on...

13 replies | 301 view(s)

January 21st, 2020, 12:23 PM

MikeS replied to a thread Commodore CBM 2001-16N - BIG MESS! in Commodore

Well, it'll certainly be a challenge that could keep you (and some of us) busy troubleshooting for a while ;-) I'd probably start by carefully...

13 replies | 301 view(s)

January 20th, 2020, 02:41 PM

dave_m replied to a thread Commodore CBM 2001-16N - BIG MESS! in Commodore

Hi Denis, Welcome to the Vintage Computer Forum - Commodore Section. It looks like your main board has been modified. Your ROM sockets seem to...

13 replies | 301 view(s)

January 18th, 2020, 07:55 PM

MikeS replied to a thread IBM Tandon TM100-2A Floppy Drive Format ? in Vintage Computer Hardware

On a single-sided drive? Remarkable!

38 replies | 708 view(s)

January 15th, 2020, 12:47 PM

MikeS replied to a thread Typewriters that acted as printers in General Vintage Computer Discussions

IIRC the interfaces I worked with and still have a few of were for the Praxis35 and a 101?

14 replies | 460 view(s)

January 15th, 2020, 12:43 PM

MikeS replied to a thread L40SX Batteries in Later PCs

Good point; 1 5/8 x 1 1/8 x 1/2

19 replies | 689 view(s)

January 15th, 2020, 10:16 AM

MikeS replied to a thread 15" and smaller VGA CRT monitors in Vintage Computer Items Wanted

Where in Ontario? It's a big place, y'know...

3 replies | 143 view(s)

January 15th, 2020, 10:14 AM

MikeS replied to a thread L40SX Batteries in Later PCs

Looks like a cordless phone battery; I use 'em in most of my systems:

19 replies | 689 view(s)

January 13th, 2020, 05:10 PM

MikeS replied to a thread Newly-acquired Model 100, needs a few parts in Tandy/Radio Shack

- I believe the battery cover has been printed - The AC adapter is 6V DC but with a negative center pin. - Cleaning battery terminals depends on...

4 replies | 158 view(s)

January 13th, 2020, 11:25 AM

MikeS replied to a thread Help identify old i8085 board (supposedly Xerox) in Vintage Computer Hardware

You're right of course, it had a 68000 and was probably a NEC after all. Should have looked more closely but that ROM board looked very similar.

16 replies | 331 view(s)

January 12th, 2020, 12:25 PM

MikeS replied to a thread KIM-1 interest? in Commodore

Good advice! Also, some papers are better than others. The same mechanism was used in some calculators but they're even harder to find these days.

15 replies | 531 view(s)

January 12th, 2020, 09:37 AM

MikeS replied to a thread KIM-1 interest? in Commodore

If it's worn down I don't think there's much you can do other than replace it; last I checked there were some available but not cheap. Turning up...

15 replies | 531 view(s)

January 12th, 2020, 09:06 AM

MikeS replied to a thread Help identify old i8085 board (supposedly Xerox) in Vintage Computer Hardware

It was just a wild guess; I scrapped a printer years ago (Xerox IIRC, could have been NEC) with a similar size board and a daughterboard with 8 or 10...

16 replies | 331 view(s)

January 11th, 2020, 05:04 AM

MikeS replied to a thread KIM-1 interest? in Commodore

A lot more than AIM65 enthusiasts :( ; I've got several of those, as well as Oscar's Nano-Kim. Looking forward to seeing those programs!

15 replies | 531 view(s)

January 11th, 2020, 04:59 AM

MikeS replied to a thread Help identify old i8085 board (supposedly Xerox) in Vintage Computer Hardware

Possibly a printer; those ROMs might be Postscript.

16 replies | 331 view(s)

January 11th, 2020, 04:54 AM

MikeS replied to a thread Toshiba T2100 documentation in Handhelds/Portables

Yeah, very confusing and a real PITA when looking for info. Why on earth did Toshiba reuse model numbers; I think there are also two different...

3 replies | 181 view(s)

January 10th, 2020, 02:49 PM

dave_m replied to a thread Pet 2001 chiclet display problem in Commodore

How about the Lunar Lander? Did it work with BASIC 4? I've been looking for it. Is it strictly command line or does it have some graphics like the PC...

275 replies | 8614 view(s)

January 9th, 2020, 01:57 PM

MikeS replied to a thread 8050 in Commodore

Thanks!

48 replies | 3854 view(s)

January 8th, 2020, 06:22 PM

MikeS replied to a thread Anyone scrapping a Thinkpad? Looking for keytops. in Vintage Computer Items Wanted

They don't look like anything on my Thinkpads; maybe from a desktop?

15 replies | 326 view(s)

January 8th, 2020, 04:28 PM

MikeS replied to a thread 8050 in Commodore

Any pics of the Mega with your board mounted?

48 replies | 3854 view(s)

January 8th, 2020, 01:44 PM

dave_m replied to a thread Pet 2001 chiclet display problem in Commodore

Congratulations on fixing this machine. What was the finally tally on bad 6550 RAM and 6540 ROM? I think BASIC 1 hanging without a 6522 is due to...

275 replies | 8614 view(s)

January 7th, 2020, 10:15 AM

MikeS replied to a thread Typewriters that acted as printers in General Vintage Computer Discussions

Hope you're not planning to use it; I just gave away a half-dozen NIB ribbons and a couple of thimbles... A while ago I finally scrapped a HiType,...

14 replies | 460 view(s)

January 7th, 2020, 09:57 AM

MikeS replied to a thread Anyone scrapping a Thinkpad? Looking for keytops. in Vintage Computer Items Wanted

I've got a few; any pics/model preference?

15 replies | 326 view(s)

January 6th, 2020, 08:41 AM

dave_m replied to a thread Pet 2001 chiclet display problem in Commodore

OK, you have BASIC 1 with the Revised H1 ROM. I forgot what Revision 1 fixed, but I think the IEEE488 its still not fully functional. If you have...

275 replies | 8614 view(s)

January 5th, 2020, 01:36 PM

dave_m replied to a thread Pet 2001 chiclet display problem in Commodore

What is the part number on the H1 ROM? Is it 901439-01 or 6540-011, then you have BASIC 1. If 901439-09 or 6540-19, then you have the the revised...

275 replies | 8614 view(s)

January 5th, 2020, 10:52 AM

dave_m replied to a thread Pet 2001 chiclet display problem in Commodore

So it looks like the 6522 VIA was keeping the PIA from issuing the 60 Hz IRQ? I suppose that is possible. You will need to replace the 6522 with a...

275 replies | 8614 view(s)

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