Hi John, Ah...theory vs. practice - sometimes it works well.... Thanks! Kind regards,DBN aka John

Hi David, Indeed, there are a few circuits that don't do well with ramping currents - thanks for the comments. Kind regards,John aka DBN Just don't do this if the 'scope has a switching Power

Hi Jim, Thanks for the comments. Kind regards,DBN, aka John

The 2465 boards are spoken for. --John Gord

I resoldered pipe 4 RAMs + resistors. My Extended Diagnostics RAM error was: Index G3A11: ▪ Area: A / j) > DmxRAM Pipe 4 And one Utility IC was dead, error was: Index G3321:

If you do a search for u800 and Thomas Lefay, you'll get his design. Although it is not completely a 100% replacement, you'll get a good idea of what's going on. Paul -- Paul Amaranth, GCIH

| | | | Re: DIY u800 repair From: Roy Thistle Date: Mon, 04 Jul 2022 13:02:16 PDT

"  From: Paul AmaranthDate: Mon, 04 Jul 2022 09:55:10 PDTActually, it was pretty good, maybe 99%. It is much better thanLafay's design and Dr Ram was continuing to tweek it to get to

"From: walter shawlee Date: Mon, 04 Jul 2022 09:37:06 PDT The re-bake program was handled by us at sphere for north american customers, but was done in Japan by an ex-Tek service center. That

Is there a schematic or detailed block diagram of what’s in the U800?

And today, 4 July only, they are offering a 30% discount. Stay safe, Ralph - W5JGV

Hi Don. Did you read the posts by Chuck Harris? Yes... been there... done that (wasn't surprised.) We... you and I... we bought a 'horse and cart': and the cart was painted real nice, and the cart's

I serviced mine, and No, you do not need a bank of fans. A ceiling fan is OK, during summer times ;-) Acquisition board has a typical fault which is caused by bad solder joints at the memory banks.

It might seem silly, but verify that each cooling fan is operating properly before popping the covers. Additionally, as I recall, operating without covers while troubleshooting required a bank of

One other important piece of information after letting the scope cool for about 20 minutes and powering back on everything passes even extended diagnostics. I am starting to think I have a cracked

It's too bad that we don't have the temperature curve. If we had the data it would be simple to program my DIY (https://www.whizoo.com/) reflow oven. Is there no chance of getting the data?

Oops. Raymond beat me to it. When is the next quiz?

I agree with Jeff. It does appear to be a 465M. To be more accurate, it is an AN/USM-425(V)1. Above the CRT bezel screw you can read the last four digits of the NSN nomenclature:

Good catch Raymond. One observation; the 455 did use LEDs in the probe coding lamps. -- Michael Lynch Dardanelle, AR

I have a DS602A that just started acting up. It has been running fine since I got it and passes self check. I have not opened the unit yet. I will have to dig it out of the rack and it is a HEAVY