Cossor CDU 150 schematics

[throbscottle]

I have just acquired one of these 'scopes in a partly working state. Does anyone have schematics for it? Channel 1 is blank unless the "pull to invert" switch is set halfway. I thought the switch was faulty but it tests ok, so looks like some problem in the ch1 amp. Think I might have blown something by mis-wiring after taking it apart to replace the same switch on channel 2 - which now works btw - previously it didn't but ch 1 did. Duh.

 

[KeepItSimpleStupid]

Looks like **broken link removed** has one cheap.

 

[throbscottle]

Massive thanks KISS - I have emailed him.

 

[throbscottle]

Dagnabbit, going to have to wait till Monday. HUFF!

 

[KeepItSimpleStupid]

I just added another scope to my collection. A Tek TDS340A 100 MHz. I'll probably convert the Floppy to a USB stick. I also ave a Kikisui 100 MHz scope. I have a Tek 211 (1 channel) and Tek 212 (2 channel) 500 KHz. that both need a little work. I'll only be able to get one to work unless I can come up with two battery holders. Right now, I only have one battery pack and the scopes won't really work witout one.

I wonder if you can do something fancy for the switch. One option that comes to mind like an opto-interrupter and a relay. Maybe something like a can type relay? That mod might be better in the long term anyway.

 

[throbscottle]

This 'scope apparently was developed in the '60's, though I think my one was made later, so I'll stick with the old tech rather than start messing about with it!

Years ago I had a Cossor which was altogether not much bigger than the tube in this one, lovely little thing, all valve, no graticule but a metal cover to protect the screen when not in use. No calibration. I wrote to Cossor to ask if they had a manual for it, but it was so old they only had one for the MKII (which had solid state rectifiers!). I made the mistake of lending it to my so-called friend, who promptly dismantled it. *******.

The only other 'scope I've owned is one that I made from the Babini book "How to build your own solid state oscilloscope". Again, uncalibrated, but it was pretty good, all considered.

So this one is /way/ advanced!

 

[throbscottle]

Drat, it's been sold

 

[KeepItSimpleStupid]

Will this work: https://www.ioffer.com/i/cossor-cdu150-(cdu-150)-oscilloscope-instructions-schem-512477093

 

[throbscottle]

Broken link - but there are a couple more there. Just rather more than I was hoping to pay...

 

[throbscottle]

I've emailed a couple of dealers who have them, also thought I'd try emailing Raytheon, who took over Cossor, see if they can help - well you never know! If these fail, Mauritron are next on the list...

 

[KeepItSimpleStupid]

The link worked for me, "Buy now" anyway. Aparently the seller is mauritron. I've gotton stuff ftom them before.

 

[throbscottle]

Huh, works now. Wonder what happened there.

The two people I've emailed can send photocopies but they cost about twice as much as Mauritron, give or take. By the sounds of it it's quite a hefty manual. Is it worth it?

 

[KeepItSimpleStupid]

I think of manuals as an insurance policy.

I think once, I got stuck, for a Meguro signal generator. Direct from the manufacturer in Japan. No schematics, over $100 USD. Had to wire the money. Other times, $100 USD has been resonable. Some instruments could have 4 mnuals 1) Operation, 2) Programming, 3) Module service, 4) Component service or technical manual and sometimes each option needs a separate manual.

It does take a fair amount of time to copy a bound manual. 70 to 100 pages is not unusual. It's even more of a pain to make 11" x 17" or A4 pages.

 

[throbscottle]

Finally ordered one from Ben Duncan Research - expensive but good quality nicely bound and includes extras from their workshop notes.