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Test Equipment Anonymous (TEA) group therapy thread
factory:
An update on the HP 512B Frequency Converter/Wavemeter.
The transformer has had the links changed for 230V operation, a temporary replacement power cord has been fitted, will do it properly at some point in the future.
Fuse value has been halved to 1A, probably 600mA would be better now I know how much power it uses (60 watts), doubt a manual exists to tell me the correct value (it's not printed in the back, as later HP TE is).
One cracked 6CB6A vacuum bulb in the multiplier circuit got replaced, luckily I managed to find one in my spares.
Bringing it up slowly with a lamp limiter was done over two weeks, had other things to do in-between, the TE desk in the house has been setup again (had been packed away while heating/radiators were being fixed, took four weeks for them to come back to finish the job :--). Nice to be able to use some of my collection of vintage TE again. :D
The wavemeter function works very well, the frequency converter part only works on some ranges, not sure how these are adjusted without a manual, thought I had a 525B (plug-in version) manual, but no I don't. The Marconi signal generator was providing the RF, the HP counter has a switched reference output at the back to provide the 100kHz and Systron DMM was monitoring the DC supply. The switch position on the 512B is added to the reading on the counter.
Edit: Forgot this picture, the HP counter checking the 10MHz multiplier output with 100kHz ref input.
David
m k:
--- Quote from: factory on September 19, 2023, 08:15:51 pm ---Well I'm getting further than I have before with the Yokogawa scope, found the setting & it seems the previous users chosen format of "2HD:1.2M" was the reason for the read error, setting to 1.44M it does seem possible to format & save files, but the Superdisk drive in the desktop PC is not reading the disk afterwards.
--- End quote ---
First you need to know what puter is actually reading.
HxD editor has Extras Open Drive, it can give you a first peek.
If first sector is meaningless you can expect that your drive can't sync with what is on the disk.
Maybe your scope used 360 rpm for 300 rpm stuff and it's too tight.
If scope can't use its own 1.2M stuff then there must be something wrong with the hardware.
BTW,
dt 30A manual is very informative, thank you.
It splits all those wafer switches to their function blocks and so make them somewhat easy to check.
factory:
Thank you, that is very helpful, a known working disk gives lots of stuff in the first sector, Yokogawa created disk is mostly blank.
I think you might be right about the drive not working correctly/wrong speed in the scope, it probably needs opening & cleaning/lubricating, just done this with the two laptop drives yesterday, the pulleys were very stiff before I took them off & oiled the bearings.
I've managed to find a belt for the Citizen V1DA-27B drive in Germany & have ordered one, the peeing caps have been replaced with Nichicon FP solid polymer types (same as I used in the Tekmeter).
I might put the Matsushita one back together with the original belt to try, now the bearings are free to turn, no visible problems with the caps in this one.
David
m k:
Since HxD can give you something it can also read something acceptably.
Sector includes many kind of out of data area stuff and those are so clear that sector is recognized.
Format few disks with the scope, 1.2M, 1.44M and 720k, can be a single disk style also.
Then read using puter and HxD.
Since you know what should be in there you can also guess how things go.
I seem to have a triple mode drive I can send to you if needed, but can't say how its health really is, even if it passes some tests.
Neomys Sapiens:
--- Quote from: factory on September 19, 2023, 08:15:51 pm ---
Well I'm getting further than I have before with the Yokogawa scope, found the setting & it seems the previous users chosen format of "2HD:1.2M" was the reason for the read error, setting to 1.44M it does seem possible to format & save files, but the Superdisk drive in the desktop PC is not reading the disk afterwards.
David
--- End quote ---
Did you already try to format for 1.44M on the PC and then write data on the scope?
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