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+--- Thread: HP 9114B Disk Drive Sensitive? (/thread-22214.html)
HP 9114B Disk Drive Sensitive? - toml_12953 - 08-23-2024 11:53 AM
Is the HP 9114B floppy disk drive particularly sensitive to interference?
When I have it to the left of my HP 82913 monitor, it seems to get a lot of disk errors and can't complete an INITIALIZE. If I move it to the right of the monitor, using the same floppy disk, it seems not to have these glitches. Is this just my imagination? coincidence? witchcraft? If it really is sensitive, is there something I can do to shield it? With my layout, I'd prefer the disk drive to be on the left side.
RE: HP 9114B Disk Drive Sensitive? - rprosperi - 08-23-2024 12:13 PM
This is odd, but it does make some sense, as when the 911B is on the left of the monitor, the drive itself (inside the 9114B case) is quite close to the monitor, while on the right of the monitor, it is necessarily further away, by the width of the 9114B case.
Of course, old CRTs are known for strong EM emissions (compared to an LCD monitor) so this is almost certainly the cause.
Try running the drive on the left side with a 'shield' in between, made of several layers of aluminum foil (or some other thin metal plate if you have it) and see if it males a difference and this should confirm your suspicion.
RE: HP 9114B Disk Drive Sensitive? - Duane Hess - 08-23-2024 07:38 PM
Don't know about the 9114B, but certainly other disk drives have verifiable sensitivity to CRTs.
Back in the early 80s we had APPLE-IIe with dual-drive units. The dual-drives had a plastic case with no shielding. If we used the APPLE monitor they peddled with IIes, which were cosmetically designed to sit on top of the dual-drive, no issue. Other brand, don't recall what, would make the drives disfunctional.
Upon examination the APPLE brand monitors had a heavy foil glued into the bottom of the CRT case. The other brands did not. Aluminum foild in the bottom of those CRTs took care of it.
Should note in the APPLE CRT the foil "plate" was not grounded. i.e. did not have a specific ground connection. Neither did the fix for the other brand CRT.
Seems foil protection added to the CRT or drive should work. One would wonder with "wrap-around" of electric fields in the monitor whether adding protection to the sides of the device might also be possible.