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I have been collecting old computers, components and peripherals for many years but recently, due to my wife's illness, I haven't had the time to devote to the hobby. Additionally, due to her need for managed care, I have decided it's time to move from our home of 33 years. This presents a...

When I power up the unit the screen displays a seek error message in three languages which is the result of a jump in the BIOS code based on an error number (9) returned to the startup routine. From what I read in the Western Digital 1773 data sheet (p. 1-7) this error is returned to the CPU by...

Reading The Personal Computer from the Inside Out by Sargent and Shoemaker (Addison-Wesley, 3rd ed., 1994) which makes reference to an included disk with a debugger referenced in the material. This book being second-hand the disk is missing. If anyone has a copy of the disk or the debugger...

Our friends at FedEx delivered a Panasonic KXP 1592 printer recently that had enjoyed their signature treatment: Several internal plastic pieces had broken. The most serious casualty was a bushing that served to orient the print-head carrier. The steel rod the head travels across sits in a...

I acquired one of these printers in a package with a 5160 XT years ago and have been searching for replacement ribbons ever since. The OEM IBM ribbons fit but are all dry by now; the replacements, beside being cheaper and flimsier, never seemed to fit. Cutting to the chase: The replacements -...

Model 850 Shugart manual states termination is required "for the seven input lines that are to be multiplexed" and that "In order for the drive to function properly, the last drive on the interface must have these seven lines terminated." The drive in question, a Model 850, had its...

CoCo 1 Cat. 26-3004 Rev. E board purchased from eBay seller two months ago, Having addressed other issues I now turn my attention to the "chicklet" keyboard which is as poor as everyone said it would be. I don't believe there are any dead keys but some require a lot of pressure, some...

In testing the unit I found that it would power up, given a 9VAC supply, but when measuring the nominal +5VDC output on the "parallel" port I found it to be 4.56 VDC. This is within range, for TTL signal purposes, but less than ideal. I have a suspicion that the root of the problem lies in the...

The Atari 850 module was designed to interface the 8-bit Ataris to serial and parallel peripherals. The computer communicates with the 850 by means of Atari's SIO bus, essentially serial but with a proprietary connector, and offers four serial and one parallel port to peripherals. An internal...

I have an old Everex IO board which has provision for a second serial port, provided you add a 1488, a 1489 and a 16450 (or 8250, say the notes). Jameco et alii have 16550s but not 16540s, so far as I can tell. I have read that the 16550 is simply a better version of the 16450, pin compatible...

Monitor suffered shipping or prior handling damage and needs repair to the front half of the case. Once upon a time someone (Chuck(G)?) wrote the following notes about disassembling the AT&T monochrome monitor: "From chuck g Using a thin-bladed putty knife and your fingers, pull away the...

Somehow this showed up complete with the 16.5VAC adapter, although I honestly don't remember when or from whence it came. It bears the Catalog # 26-1176 and is described (Thanks, Ira! * ) as a Bell 212A standard modem from the 1980s. $399 when new; that's about $1000 in today's dollars. It...

In 2020 various members discussed "AT&T PC 6300 BIOS 1.1 ROM dump" and the point was made that merely updating ROMs would not suffice, as there were differences in the motherboard components as well. One of the respondents, Trixter, mentioned that he had to replace 2 PALs to bring his 1.21 ROM...

Newly acquired AT&T PC6300 boots and appears to be fully operational, but observing the display the letters appear taller at the top of the (monochrome) screen and shorter at the bottom. This is confirmed with the Customer Diagnostics tests which show a pattern of concentric figures; they are...

I received by FedEx yesterday a Model 1 Color Computer (3004). Upon examination I discovered the bottom of the case was cracked in the left rear corner, near the transformer and power supply. This probably happened in transit. This was an eBay purchase and with the consent of the seller I...

Reading Thomas Windeknecht's 6502 Systems Programming, in which he outlines assembly routines using an assembler, BREVITY, of his own design. Does anyone have a copy of this or the related files? Thanks, -CH-

At VCF West Michael Steil delivered a talk about disk drives, using the Commodore 1541 as his example. I greatly regret missing this talk and am wondering if a copy, either text or video, is available. I'm posting this request here in hopes that someone who knows Michael might forward it to his...

Recently I set aside the Model III I had been using for experiments because the second (top) drive, designated by the OS as ":1", began to misbehave. In a short period of time it went from reading and writing reliably to not being able to read a disk at all. The drive light would come on, the...

In transferring files from a Win10 machine to the M4 via a serial connection (9600 / 8N1 / RTS CTS DSR = ON, CD RI = OFF) I am reliably transferring one file at a time using XMODEM. Attempts to use YMODEM for batch transfer have thus far failed. (Receiver reports missing header on file save)...

Yesterday I brought up the 586 AMD VLB that I had installed OS2 Warp 3 on some time ago. Apart from some hardware issues** the most annoying problem was the OS itself; I think I should upgrade to Warp 4. I see on WinWorld there are versions 4 and 4.52. Would I be advised to upgrade to 4...