View Profile: BTX - Vintage Computer Forum

Yesterday, 08:40 PM

modem7 replied to a thread IBM PC 51xx real number of pieces produced? in PCs and Clones

The diagram is from the March 30, 1987, issue of INFOWORLD magazine. If the Wikipedia article on the 5140 (IBM PC Convertible) is to believed, the...

9 replies | 157 view(s)

Yesterday, 12:36 AM

modem7 replied to a thread Seagate ST-412 stuck (spindle not spinning) in Vintage Computer Hardware

It has been established that the OP's ST-412 and my ST-412 do not have a physical spindle brake. That infers that the engineers of our drives were...

22 replies | 268 view(s)

December 10th, 2019, 06:09 PM

modem7 replied to a thread Seagate ST-412 stuck (spindle not spinning) in Vintage Computer Hardware

Yes, it appears that there were variations of the ST-412. On page 36 (PDF page 44) of the manual at here] is, "Spindle Brake (models with Motor...

22 replies | 268 view(s)

December 10th, 2019, 03:21 PM

modem7 replied to a thread Seagate ST-412 stuck (spindle not spinning) in Vintage Computer Hardware

In case of use for anyone later, I have been able to reduce that configuration. In my functional ST-412, for the spindle to rotate, all I need to do...

22 replies | 268 view(s)

December 10th, 2019, 02:30 PM

modem7 replied to a thread Wanted: IBM 5153 Color Display (or a look-and-workalike - PGS HX-12?) in Vintage Computer Items Wanted

For the 5160's PSU, the 130W rating is in regards to the DC output voltages (per here]), i.e. excludes the auxiliary power output. A step-down...

5 replies | 158 view(s)

December 10th, 2019, 01:40 PM

modem7 replied to a thread Seagate ST-412 stuck (spindle not spinning) in Vintage Computer Hardware

That thing grounds the spindle. During this time of diagnosis, it can be removed. I see no braking mechanism. Confirm for us that the 5 mm...

22 replies | 268 view(s)

December 10th, 2019, 01:13 PM

modem7 replied to a thread Seagate ST-412 stuck (spindle not spinning) in Vintage Computer Hardware

My ST-412 does not have a spindle brake. On your ST-412, do you see anything extra (mechanical that is) to what is shown in the photo at here] ? ...

22 replies | 268 view(s)

December 9th, 2019, 02:21 PM

modem7 replied to a thread DEAD - NEC PowerMate 1 Plus (APC-H2010F) 80286 in Vintage Computer Hardware

No. For example, the power supply in the IBM PCjr does not generate a POWER GOOD signal (or equivalent). Instead, motherboard reset at power-on...

8 replies | 133 view(s)

December 9th, 2019, 02:09 PM

modem7 replied to a thread Seagate ST-412 stuck (spindle not spinning) in Vintage Computer Hardware

Welcome to these forums. Yes. The spindle noise of an ST-412 is very noticeable. And if you put your hand on the top of the drive, you can feel...

22 replies | 268 view(s)

December 9th, 2019, 01:17 PM

modem7 replied to a thread DEAD - NEC PowerMate 1 Plus (APC-H2010F) 80286 in Vintage Computer Hardware

Yes. Do you know if your motherboard requires a POWER GOOD signal (or equivalent) from the PSU? In most AT-class motherboards, the motherboard...

8 replies | 133 view(s)

December 8th, 2019, 02:25 PM

modem7 replied to a thread DEAD - NEC PowerMate 1 Plus (APC-H2010F) 80286 in Vintage Computer Hardware

Your second post has appeared. Looking at the datasheet, from an electrical perspective, I cannot see why not. There is though, a remote...

8 replies | 133 view(s)

December 8th, 2019, 02:22 PM

modem7 replied to a thread Wanted: IBM AT case faceplate in Vintage Computer Items Wanted

You already have items 4 and 6 ?

4 replies | 137 view(s)

December 8th, 2019, 01:52 PM

modem7 replied to a thread Stepper motor problems with Panasonic JU-475 floppy drives in Vintage Computer Hardware

Different make-model of drive, but supports suggestions of some earlier posts: * The thread at here] is about a YD-380 drive 'making very strange...

16 replies | 228 view(s)

December 8th, 2019, 01:23 PM

modem7 replied to a thread Wanted: IBM AT case faceplate in Vintage Computer Items Wanted

So that readers are clear about what exactly you mean by "faceplate": Refer to page 7 of the IBM document at here]. Which number, or numbers, are...

4 replies | 137 view(s)

December 7th, 2019, 08:01 PM

modem7 replied to a thread DEAD - NEC PowerMate 1 Plus (APC-H2010F) 80286 in Vintage Computer Hardware

Welcome to these forums. With the majority of AT-class keyboards that I have tried it on, simply connecting power only to the keyboard, results...

8 replies | 133 view(s)

December 6th, 2019, 03:42 PM

modem7 replied to a thread ibm 5151 blinking cursor then shuts off in Vintage Computer Hardware

S1 and S2 is the secondary of the power transformer. The SAMS circuit diagram of the power supply, at here], shows that when your 5151 is working,...

6 replies | 229 view(s)

December 5th, 2019, 01:24 PM

modem7 replied to a thread Action Replay PC (ISA card): manual, box, disk, PCB scans in Vintage Computer Hardware

I have hosted the files at here], in the Datel section. Within the PDF of the instruction manual, I performed OCR (which also de-skewed pages),...

4 replies | 130 view(s)

December 4th, 2019, 05:35 PM

modem7 replied to a thread ibm 5151 blinking cursor then shuts off in Vintage Computer Hardware

Regarding symptom #1. It sounds like the symptom is triggered by heat: When the symptom appears, the symptom 'cause' cools down, and everything...

6 replies | 229 view(s)

December 4th, 2019, 01:03 PM

modem7 replied to a thread ibm 5151 blinking cursor then shuts off in Vintage Computer Hardware

I see two symptoms, with different causes: #1. 5151 shutting down. #2. Unexpectedly seeing only a blinking cursor when the 5151 is moved to a...

6 replies | 229 view(s)

November 30th, 2019, 10:55 PM

modem7 replied to a thread Seagate ST-4053 and IBM AT in PCs and Clones

NOTE: Below is for IBM DOS 3.3 - other makes/versions may have different behavior. 1. I brought out my IBM XT, which is fitted with a 20MB 'MFM'...

30 replies | 976 view(s)

November 30th, 2019, 09:35 PM

modem7 replied to a thread Seagate ST-4053 and IBM AT in PCs and Clones

It is MFM.

30 replies | 976 view(s)

November 30th, 2019, 07:55 PM

modem7 replied to a thread Seagate ST-4053 and IBM AT in PCs and Clones

If one starts Speed Disk, then chooses not to perform the optimise operation, then Speed Disk shows the current block map (distribution of used and...

30 replies | 976 view(s)

November 30th, 2019, 03:30 PM

modem7 replied to a thread Seagate ST-4053 and IBM AT in PCs and Clones

That is not how I am seeing IBM DOS 3.3 behaving (as observed via the 'block' map in Norton Speed Disk). I expect that over the years, Microsoft...

30 replies | 976 view(s)

November 30th, 2019, 02:31 AM

modem7 replied to a thread Seagate ST-4053 and IBM AT in PCs and Clones

But maybe the POST in that 386 does not try to read the last track. The POST authors do not need to copy IBM. And DOS is probably not going to...

30 replies | 976 view(s)

November 28th, 2019, 09:31 PM

modem7 replied to a thread Generic IBM AT Power Supply in a IBM 5150 in PCs and Clones

It does. See the 'Modern power supplies' section at here].

43 replies | 851 view(s)

November 28th, 2019, 02:11 PM

modem7 replied to a thread Plus Hardcard 20 error in Vintage Computer Hardware

Imagine that sometimes, at 5150 power on, the spindle motor in the drive is unable to overcome 'head stiction' to spin the platter. If that...

11 replies | 297 view(s)

November 28th, 2019, 12:44 AM

modem7 replied to a thread IBM EGA Card Memory Expansion Boards in PCs and Clones

The photos at here] show how close the IBM Graphics Memory Expansion Card comes to the adjacent card in an IBM 5170. Clearly, that is why the IBM...

14 replies | 418 view(s)

November 28th, 2019, 12:02 AM

modem7 replied to a thread Plus Hardcard 20 error in Vintage Computer Hardware

"1701" is generated by the BIOS expansion ROM on the Plus Hardcard (and other XT-class hard disk controllers). Part of the code in that ROM gets...

11 replies | 297 view(s)

November 27th, 2019, 10:10 PM

modem7 replied to a thread ISA Floppy/Game/Serial/Parallel Card in 5150? in PCs and Clones

There were many different models. I suggest that you should avoid any for which you cannot locate switch/jumper setting information. Manuals for two...

9 replies | 278 view(s)

November 27th, 2019, 09:53 PM

modem7 replied to a thread IBM 5150 troubleshooting in PCs and Clones

Yes, under the large and medium sized aluminium electrolytic capacitors is glue. Line suppression capacitors are supplied in various forms. In...

18 replies | 482 view(s)

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