Re: Very Inexpensive 7623A, but Problems



If yours is a storage scope the HV is really in the HV supply and on the storage board as far as I know. The main 7000 series goes up to a 130 V supply but there is a -4Kv supply for the tube which if I remember correctly is fed in to a voltage tippler which will give you an acceleration voltage of about 12Kv on the fat red wire. Not a tone of current there but it is still jumpy and nothing to mess with. My storage experience is limited to the 577 curve tacers but in there the storage flood guns get a 300 ish volt supply and the deflection plates are driven by 200 odd volts. I do recall that in one of my 7603's there was a bad driver transistor in the LV supply for the pass element. This caused my 130V rail to be off in the weeds at about 149V all because the pass transistor was not being told what to do. There are a couple of power supply design changes the very original 7603's were fan less and had a plastic cover. The metal ones I think have the fan.

Good luck with the restoration.


-----Original Message-----
From: <> On Behalf Of Jeff Dutky
Sent: Saturday, February 13, 2021 1:33 PM
Subject: Re: [TekScopes] Very Inexpensive 7623A, but Problems


Thank you for the warning.

I paid $60+$35 shipping. It's not quite peanuts, but it's also not quite dinner out with the family.


I will be taking lots of pictures.


There are lots of socketed ICs (and transistors) to be sure. I will check those after I've done my visual inspection and read the manual a bit (there's lots of warnings, printed on the frame it RED LETTERS, about high voltages. This is an entirely different beast than my 475s and 2200s).

-- Jeff Dutky

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