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Thank you for the part numbers and checksums for the ROMs. Unfortunately I do not have an EEPROM programmer so am unable to verify the checksums or program new ones. I would need a bit of help

John, I have a 468 as well but have not used it in a very very long time. Unless a near impossible part to find part has burned out it should be repairable. Since this is a processor controlled scope,

I recently acquired a Tektronix 468. When powered up (with digital mode turned off) it will occasionally display a good trace but usually there is no horizontal sweep. The time-base is working but the

It must be you. I have some four posts from him which are ok. I get my messages as emails and use Outlook 2010. Colin.

If, like me, you are using the web interface you have to click on 'show quoted text' to see what Ray has written. Like so many other web things, I don't know why, but it works. Roger

Nothing. Is it just me, or everytime that "Ray astrodroid@..." posts something there's zero content?

Hi Colin, I'm pretty sure I have one I can spare. I have to take the knob off one of my 7A22s to see if this knob fits the shaft and the middle knob fits into it. Contact me off list. Dennis Tillman

Yes. Sometimes you can clear the short without also damaging the semiconductor element, and the OP should try it. I've done it, by shorting EBC together and applying voltage between them and the can.

Thanks a bunch Dave. That is great info. I will definitely do some experimenting with your recommended substitutes. I have very little transistor stock since I build/restore tube gear almost

Thanks a bunch Morris. Yes, that helps! I figured it had to be one of those two transistors, but while they are easy to remove/replace physically, I was trying to find where the EBC leads wound up on

It is perhaps worth noting that the tin whisker problem is a function of age, not of the time powered up, so NOS transistors in that package have the same likelihood of having whiskers as any other of

That will appeal to people who just want their scope working and don't get a big kick out of re-engineering it as I do. I think my hobby niche is becoming "retrofit engineering". Dave Wise

There's a slew of what look to be real deal NOS 2N2207s on eBay, here: https://tinyurl.com/yyjt6vku Best, Bill

For Q173 and Q373, the critical attributes are Cob and BVcbo. Q184 same except Cob is not top priority. My best results were BC556 and KSA992. Both required extra speedup capacitance. MPSA56 was okay

Agree, Ram stby current should be in that neighborhood if no other extraneous leakage. New battery is on the way, so will measure current before installing it. BTW wanted to mention that in those 8

Hi! I'm looking for a program called "pulse parameter analysis" which was provided by Tektronix in the 70ies. I've uploaded a short program description and an unsharp picture from the original manual

You might look at this YouTube for a brutal but effective way of recapping boards. https://www.youtube.com/watch?v=X8N9O3a9jiM Smon

This problem has been discussed here in the past. A common loss of B sweep intensification (not actually retrace blanking) is caused by failure of either or both Q184 or Q173, both fast pnp germanium