View Profile: ldkraemer - Vintage Computer Forum

Today, 06:34 AM

ldkraemer replied to a thread Help, I am lookin for a modifacation for my model 1 system in Tandy/Radio Shack

Rick, So, you are going to use a stock Model 1 keyboard, and the EI that has zero memory installed. If so, then all you need to do is add the two...

3 replies | 71 view(s)

Today, 02:47 AM

ldkraemer replied to a thread Help, I am lookin for a modifacation for my model 1 system in Tandy/Radio Shack

Rick, Your best bet is to keep the 64K RAM IC's in the Keyboard and not add any memory to the EI. The 64K RAM is a lit better than the Older RAM...

3 replies | 71 view(s)

Yesterday, 12:30 PM

clh333 replied to a thread 70 Mb HD Documentation Needed in Tandy/Radio Shack

After a lengthy siesta, back to this topic: The attached pictures illustrate the non-standard wiring and modifications to that non-standard wiring...

6 replies | 592 view(s)

Yesterday, 02:56 AM

ldkraemer replied to a thread Commodore 1541 drive can't format or read disks in Commodore

What is the Device Number of the Drive? 8, 9, 10, 11 ?? After you format the Floppy, Did you Initialize it? What was the Read Error? Send...

6 replies | 67 view(s)

January 13th, 2021, 02:30 PM

clh333 replied to a thread Soldering station heating element replacement in Vintage Computer Tools

I obtained a Hakko 1321 heating element and installed it in the Zeny iron. The specs are the same and the leads are long enough but the Hakko board...

3 replies | 142 view(s)

January 12th, 2021, 03:14 PM

ldkraemer replied to a thread Problem with Expansion Interface in Tandy/Radio Shack

Rick, I have no knowledge of what the FreHD auto boot ROMS do. I think you need Ian involved. Larry

4 replies | 103 view(s)

January 12th, 2021, 08:23 AM

ldkraemer replied to a thread Problem with Expansion Interface in Tandy/Radio Shack

Rick, Can you answer the following questions? 1. What version ROM is in your model 1? ver 1.1 or 1.3? 2. Do you know if it is the 3 ROM set or...

4 replies | 103 view(s)

January 7th, 2021, 12:03 PM

clh333 replied to a thread Model 4P First Questions in Tandy/Radio Shack

After a few twists and turns I have the machine back together, having rebuilt the PSU, added another 64k memory and repaired or replaced the Tandon...

9 replies | 483 view(s)

January 6th, 2021, 02:09 PM

clh333 replied to a thread Soldering station heating element replacement in Vintage Computer Tools

Thank you for the suggestion; I think maybe not. I have ordered a couple of HAKKO elements after inspecting the Yihua and researching its specs. ...

3 replies | 142 view(s)

January 5th, 2021, 01:32 PM

clh333 started a thread Soldering station heating element replacement in Vintage Computer Tools

Sorry for asking another dumb question but this is my first time through this problem. Graduated from the "pencil" soldering iron (Radio Shack...

3 replies | 142 view(s)

January 4th, 2021, 05:20 PM

ldkraemer replied to a thread Model 4 Non-GA Garbage at power on in Tandy/Radio Shack

Bill, I'd just go back and check A{0..15} using the Pullup Resistor and checking the HIGH and LOW Voltages on the Address Lines to the ROM(s). If...

61 replies | 3806 view(s)

January 4th, 2021, 06:30 AM

ldkraemer replied to a thread Model 4 Non-GA Garbage at power on in Tandy/Radio Shack

Bill, The replay from David was years ago and I had saved it in a Note under my Model 1 folder. Sorry for the confusion. Try holding down the...

61 replies | 3806 view(s)

January 4th, 2021, 06:16 AM

ldkraemer replied to a thread Kaypro 4/84 in CP/M and MP/M

Here is a bit more information I OCR'd. CHARACTER ROM D3 A 2716 (2K x 8) EPROM is used to store the dot information for every character...

4 replies | 209 view(s)

January 3rd, 2021, 04:26 AM

ldkraemer replied to a thread Tandy 1000 EX Gotek in Tandy/Radio Shack

I've created three screenshots of the Floppy layout and the dummy disk screenshot. Also exported the *.HFE file for booting on the GOTEK...

2 replies | 206 view(s)

January 3rd, 2021, 03:19 AM

clh333 replied to a thread Linux: Upgrade version or reinstall? in General Off Topic

Just yesterday I upgraded one of the machines from Fedora 32 to Fedora 33. Because of its location it had been receiving update by wi-fi, but the...

56 replies | 3359 view(s)

January 2nd, 2021, 03:27 AM

clh333 replied to a thread Need TRS-80 Model IV software on disk! in Tandy/Radio Shack

Ian Mavric offers software on disk for several different TRS Models. See: http://members.iinet.net.au/~ianmav/trs80/ -CH-

4 replies | 223 view(s)

December 31st, 2020, 08:23 AM

ldkraemer replied to a thread Model 4 Non-GA Garbage at power on in Tandy/Radio Shack

Bill, I'm 99% sure you have the problem fixed with the HIGH on A6 with a LOW on the Input as shown by the following SN74LS244 Photo. Larry

61 replies | 3806 view(s)

December 31st, 2020, 06:50 AM

ldkraemer replied to a thread Model 4 Non-GA Garbage at power on in Tandy/Radio Shack

Bill, I found a previous note that David Miltimer had posted about {A7..A15} for the Model 1. I had forgotten about it, until I was searching for...

61 replies | 3806 view(s)

December 31st, 2020, 06:32 AM

ldkraemer replied to a thread Fred the Floppy's Repair Log (8050M) in Commodore

Lithium Grease will attract Dirt/Dust. Why not use some Dri-Slide (a Motorcycle cable lubricant that does not attract dirt/dust)? It available at...

37 replies | 1262 view(s)

December 29th, 2020, 05:32 AM

ldkraemer replied to a thread Hi from Spokane, WA in Introductions

Bo Zimmerman has lots of Commodore Info here: http://www.zimmers.net/ http://www.zimmers.net/commie/index.html...

2 replies | 179 view(s)

December 28th, 2020, 03:02 PM

ldkraemer replied to a thread Model 1 Video RAM issue(s) in Tandy/Radio Shack

Let's start with the first screen and understand it. It is as follows: MEM@SIZE @@@@@@@@ which has 7 spaces between the two character strings...

2 replies | 152 view(s)

December 28th, 2020, 04:24 AM

ldkraemer replied to a thread PC XT Power Supply Repair in PCs and Clones

Here are a couple Schematics I found somewhere on the Internet. It has the same Transistors. AT_compow11.gif ATX_psu_schematic.pdf Send me a...

15 replies | 893 view(s)

December 26th, 2020, 06:30 AM

ldkraemer replied to a thread Osborne 1 "BOOT ERROR" on Drive A: only, help diagnosing.. in CP/M and MP/M

The Drive Select Signals originate from Sheet 5 Area B5 and go to Sheet 9 Area A8. Larry

2 replies | 167 view(s)

December 25th, 2020, 03:56 AM

clh333 replied to a thread Merry Christmas! in Tandy/Radio Shack

Woke this morning to find a foot of snow had fallen overnight. To me that's beautiful. Merry Christmas to all, and thanks for all you've done. ...

2 replies | 226 view(s)

December 24th, 2020, 04:17 AM

clh333 started a thread Model III / 4 cassette-based files in Tandy/Radio Shack

Does anyone know of a repository for programs that were developed to run on the Model III or 4 and were released on tape? Maybe stored as WAV files?...

1 replies | 150 view(s)

December 22nd, 2020, 05:29 AM

ldkraemer replied to a thread WANTED: Eagle CP/M Computer mainboard repair in Vintage Computer Services Offered/Needed

I had previously had extracted the files from an Eagle Image File and the "EBIOS.ASM" file can help you build a small test routine. Send me PM...

11 replies | 697 view(s)

December 21st, 2020, 07:56 AM

ldkraemer replied to a thread WANTED: Eagle CP/M Computer mainboard repair in Vintage Computer Services Offered/Needed

I located the Service Manual for the Eagle on Bitsavers. It explains the 8002 and 5037 pretty well. p.46 p.129

11 replies | 697 view(s)