Tektronix 475 Oscilloscope

[Doc Stitches]

Don't know if this is off topic,..... If it is I will delete it right away.

but here is the deal.....

The display and fan just stopped working...any ideas?

The 3 small UNCAL lights come on.

The 2 fuses are good and the selector switch bar is in the medium position and test good.

Thanks
Doc

[Enzo]

I'd say you have a powr supply failure.

[Axtman]

Maybe these forums can help you.

tektronix forum: Tektronix Forum • View forum - Oscilloscope Technical Support

Antique Radio test equipment forum: Antique Radio Forums :: View Forum - Test Equipment Discussions

[Doc Stitches]

Thanks, Enzo.

[Doc Stitches]

Thanks, Axtman...I'll check those sites.

[JoeM]

Doc,

Check out the Tekscopes group on Yahoo. Several retired Tek employees over there. I have a few Tek scopes, and they've been a big help to me in repairing them.

TekScopes : All about classic Tektronix CRT o'scopes

[radtekvp]

Check the caps

With a scope of that age you can look right at the filter caps. Tek scopes often have a shutdown feature that will kill the supply if ripple exceeds an overvoltage limit.

[loudthud]

Many times in a Tektronix scope one power supply is adjustable and all the other (usually 5 or more) supplys use it as a reference and their voltage is determined by 1% resistors. If that supply dies, all the others go down except some loosely regulated supplys for panel lights. I may have a service manual for the 475 or have access to one. It will take a couple of days to look for it.

[JoeM]

Couple of sources for Tek Manuals:

http://bama.edebris.com/manuals/tek/

Tektronix Service Manuals

[Gtr_tech]

I have a 475 200mhz version with the DM44 meter on top. Works fine with the exception that the trace doesn't seem to be as fine as it should...IE a little too tall when focused. I'm sure its due for a cal and some cap replacement. Paid $25 for it with a bunch of probes. I keep it as a backup. Haven't needed it yet...the trusty B&K just keeps on a-goin'.

[JoeM]

I have a 475 200mhz version with the DM44 meter on top. Works fine with the exception that the trace doesn't seem to be as fine as it should...IE a little too tall when focused. I'm sure its due for a cal and some cap replacement. Paid $25 for it with a bunch of probes. I keep it as a backup. Haven't needed it yet...the trusty B&K just keeps on a-goin'.

Most Tek scopes that dont use tubes like the old 500 series have a screen mesh in the CRT order to get the high bandwith, this does cause the trace to not be as sharp as the older tube models.