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Type: Posts; User: Hugo Holden

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  1. Good suggestion. I was wondering that if 4F pin...

    Good suggestion. I was wondering that if 4F pin 10 was stuck low, it wouldn't inhibit the clocking of both flip flops and not affect both directions, not sure but worth checking as it could be a...
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    Thanks, I will try this combined with the code...

    Thanks, I will try this combined with the code from post #4 and assuming I don't foul up the instructions to the assembler, it should work.
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    In my 5155 I have a "Unique" brand floppy...

    In my 5155 I have a "Unique" brand floppy controller that supports two floppy drives. I installed a dual 3.5/5.25" Teac drive unit in one bay and a Seagate ST256 HDD in the other bay. It all worked...
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    Can you suggest the lines of code you would use...

    Can you suggest the lines of code you would use (which will help me to avoid any errors initially getting the filename effective address into dx)
  5. I think you are right about this. A while ago I...

    I think you are right about this. A while ago I came across a vintage avionics grade video/radar monitor the whole thing impressed me so much that I copied the entire schematic out by hand and wrote...
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    Chuck, does that mean I can use the PSP +81h as...

    Chuck, does that mean I can use the PSP +81h as the effective address for the filename prior to the start of the code listed in post #4 ? or would it require more steps ?
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    Thanks. Can you show me the code which will parse...

    Thanks. Can you show me the code which will parse a file from the command line ?
  8. The two vintage computers I have, SOL-20 and...

    The two vintage computers I have, SOL-20 and IBM5155.

    The SOL needed its keyboard pads replaced and a total of 10 faulty IC's (some belonging to the main board including RAM IC's, others to the...
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    The record size doesn't matter too much, I just...

    The record size doesn't matter too much, I just got used to it in CP/M

    Thanks, I will try this code.

    The reason I want to keep the starting address hard coded is that a number of smaller...
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    Yes, I have used Debug for this and it works...

    Yes, I have used Debug for this and it works well, but ideally I need a .exe program that does it quickly for any named file on the floppy in my 5155.
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    DOS Disk file access help.

    Initially I tried to access disc files in CP/M using the file control blocks (FCB). It all worked very well, open the file, zero a record counter, set the DTA to my preferred address read a record...
  12. One thing with a circuit like this is that it is...

    One thing with a circuit like this is that it is more difficult to see what it is doing, or can do, with IC's 1A , 2A and 2B drawn as NAND gates because to get a change in output(going low) all...
  13. Yes it will be easier if you know exactly what it...

    Yes it will be easier if you know exactly what it is being fed with. If it were just an S-R latch it would have only required a couple of NAND gates. The circuit appears to be similar to a D flip...
  14. It appears to be a variant of a D flip flop.As a...

    It appears to be a variant of a D flip flop.As a rough guess:

    Pad6 = /Q output
    pad3 = /preset
    pad2 = Clock (positive edge triggered)
    pad1 = data input
    pad4 = High enable, or possibly act as a...
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    The DRAM IC's must have been an awful lot cheaper...

    The DRAM IC's must have been an awful lot cheaper also to offset the costs of the extra IC's and circuitry on a DRAM S-100 card compared to an SRAM card of the same capacity. Now there doesn't seem...
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    In this case it is definitely the IC. Since I...

    In this case it is definitely the IC. Since I didn't have any of these IC's on hand I swapped the defective one with a good one higher up in memory and the faulty IC takes the defect with it to the...
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    One really good place to buy beautiful quality...

    One really good place to buy beautiful quality vintage parts from is Japan. Japanese versions of devices and their own versions always seem to be very well made and the Japanese conduct themselves in...
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    Double checked the device actually on the pcb its...

    Double checked the device actually on the pcb its an LS04. I probably should put a 100R resistor in there at least, but I would have to modify the board, cut a track etc... hmmm.... maybe just leave...
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    There is a little oddity on this Yang board....

    There is a little oddity on this Yang board. There is an indicator LED which it driven on when any of the 16 memory chip select lines are active, the odd thing is that the designer didn't put a...
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    I have repaired the Yang board. And it works in...

    I have repaired the Yang board. And it works in the SOL-20. There were two issues. It has jumpers for normal S-100 mode addressing and another mode used with the YES-5 computer. But the silk screen...
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    There are a number of outcomes from the "Parts...

    There are a number of outcomes from the "Parts Recycling & cloning" industry when it comes to semiconductors:

    1) Cloned new manufactured parts. Might or might not reach spec of original part.
    ...
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    Thanks Mike. Of course. So now there are two...

    Thanks Mike. Of course.

    So now there are two ways to spot a likely compatible RAM board for the SOL - 20:

    If its DRAM it must not use pin 66.
    If its SRAM its ok.

    I'll report what was wrong...
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    Thanks. I just checked on the Yang board, pin...

    Thanks.

    I just checked on the Yang board, pin 66 not used. Si I think one of the IC's has failed probably in the address decoder as it has an LED that is supposed to light hen the board is...
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    Interesting, these boards carry the same HM6116P...

    Interesting, these boards carry the same HM6116P IC's as the Yang board I have been trying to get to work (but the Yang simply has half the number as its 32k) The photo of the Yang board is on this...
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    Thanks, so its a hardware issue. I have tried...

    Thanks, so its a hardware issue.

    I have tried a Seatle Computer Products (SCP) 16k Ram card in the Sol-20 and it works fine. But I'm wanting a higher capacity single card and looking around at...
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