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H-17 FDD Rotational Speed Problems

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#1 of 8 Posted Oct-28 10:01 PM

From Doc Bogner Posts 674 Last Nov-9
To reavis86vic [Msg # 136751.1 ]

<< One of the Floppy Drives (Siemens) that I have cannot be adjusted to the proper speed. It is obviously higher than 200, but the Go:7372 test gives a strange number, like 130774 instead of 000xxx which I expected. Any ideas? >>

There are several possibilities. We can narrow it down with your answers to these questions:

1. Since you have more than one H-89, is it safe for me to assume that you're using a known good H-88-1 Single-Density Controller Card with the Siemens FDD that has the rotational speed problem?

2. Is your FDD a Siemens model FDD100-5?

3. Does your FDD have a strobe label on the spindle motor pulley?

4. On the suspect FDD, are you able to vary the rotational speed using either R7 or R30 on the rectangular servo board mounted behind the spindle motor pulley?

Doc

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#2 of 8 Posted Oct-29 11:14 AM

From reavis86vic Posts 9 Last Nov-12
To Doc Bogner [Msg # 136751.2 136751.1 ]

Thanks, Doc

1) Yes, I am using a good H-88-1 controller card. The speed of the currently installed FDD is adjustable to 200 using the rotational test program from the GO: prompt (I don't remember if it is 7372 or 7273). When I connect the troublesome FDD into this system, I get a weird number to that test, like 134,704.

2) The FDD is a Siemens model FDD 100-5 (as is the good one mentioned above).

3) There is a strobe label on the spindle (larger)

4) The speed does not appear to vary by adjusting the resistor, which is located just below the large spindle with the strobe label. The numbers from the rotational test program mentioned in (1) above do vary slightly with adjustment of the resistor, but they also vary slightly as the test runs, so I am uncertain if adjusting the control actually affects the speed.

Reavis

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#3 of 8 Posted Oct-29 5:11 PM

From Doc Bogner Posts 674 Last Nov-9
To reavis86vic [Msg # 136751.3 136751.2 ]

You're welcome.

Please let me know if your FDD 100-5 servo board's speed adjustment pot is silkscreened as R7 or R30.

Next, let's determine if there's actually a speed problem on the FDD, or if the problem is a data reporting error among the drive, the controller card, and the computer.

Start a rotational speed test using Go 7372. While the spindle motor is running, use the strobe label on the spindle pulley to determine if the R7 or R30 pot adjustment is making any difference. Assuming your H-89 is operating on 60 Hz AC, just watch the outer strobe band (labeled "60") as you adjust R7 or R30 from one extreme to another. Ignore the speed test numbers reported on the monitor. If the pot is functional, the blocks in the outer strobe band will appear to be stationary when the spindle motor is operating at 300 RPM ( = 200 octal). Even if you can't adjust the pot to achieve this goal, changes in the appearance of the strobe band will tell you if the pot is making any difference in the spindle motor speed.

Doc

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#4 of 8 Posted Oct-30 2:28 PM

From reavis86vic Posts 9 Last Nov-12
To Doc Bogner [Msg # 136751.4 136751.3 ]

Thank you, Doc. Because of other commitments, I won't be able to work on this project for several days. I will provide the requested information in a post in 5-7 days.

Reavis

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Message 136751.5 was moved to 136752.1

#6 of 8 Posted Oct-30 5:37 PM

From Doc Bogner Posts 674 Last Nov-9
To reavis86vic [Msg # 136751.6 136751.4 ]

You're welcome.

Thanks for letting us know that there will be a brief intermission. We're working on this issue at your pace.

Doc

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#7 of 8 Posted Nov-6 10:49 AM

From reavis86vic Posts 9 Last Nov-12
To Doc Bogner [Msg # 136751.7 136751.6 ]

OK, Doc, I'm back

The pot controller on the board is R7.

When the disk drive is running, I cannot see the strobe lines. However, if I put my finger on the motor spindle and slow it down by applying gently pressure, I can see them. Adjusting the pot made no discernable difference.

Reavis

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