Telequipment D67 Repair

[pompeiisneaks]

I've gotten a Telequipment D67 for cheap, 20 bucks but it's not working.  I power it on, and it has a trace on the scope display, but no input seems to ever arrive there. 

I tried finding a schematic and all I can find is the D67A which is very different from the beast I have in front of me (components in the service manual are numbered differently, etc.)

First, does anyone have a schematic for the D67?  I've seen something online for sale for 30$ but that's more than the cost of the scope itself, and I was wary of the site, seems possibly a malware haven.

Second, anyone have much knowledge of these? 

I did get my scope out and trace the signal I input (a 400mV 1000Hz sine from an hp 200CD) most of the way through the first board, connected to the inputs, but it stops just shy of the actual area that connects to the scope.  Since I've no idea where to really look, I'm seeking advice/help/ideas?

Thanks!

First time post, long time EEVBlog viewer

~Phil

[tautech]

Welcome to the forum.

Yes a free D67 manual is an elusive beast and the best selection of Telequipment manuals I could find was here:
https://elektrotanya.com/
Just use Telequipment as the search for 2 pages of them.
They have D65, 66 and 67A so between them all you should have enough to help you out.
In my searches I also came across this D67 three page thread:
https://antiqueradios.com/forums/viewtopic.php?f=8&t=285530
They talk a little about the differences between 67 and 67A where apparently some of the wattage ratings of resistors were upgraded in the 67A which in itself might offer clues to your fault in the way of a drifted resistor or even open.
Many back then were carbon comp and drifted like crazy especially if they were under any HV loadings.
Nevertheless there's some good info in that thread that may be of assistance.

Ex D83 owner.

[pompeiisneaks]

Thanks for the info.  I'll try and look at the D65 and 66 as you say, see how close they are.  I do already have the 67A but definitely got confused as it seems quite different.  I can't compare parts numbers or find them etc.  I too recall finding that thread in my searching but maybe due to my lack of deeper understanding of the complexity of the scope circuit here, I didn't understand enough to 'follow' if that makes sense.  He specifically stated that some of the circuits were quite different from the 67A as well. 

Thanks again for the information!

~Phil

[tautech]

I suggest you do some reading about CRO theory and study other brand CRO schematics. All in all the basics are the same especially in CRO's of this vintage.
Also grab the Tek troubleshooting pdf from the Repair links thread at the top of this board.

Really there are just a few main blocks to a CRO; PSU, EHT PSU/generation for the CRT, Timebase and the vertical signal path. Get a handle on each of them and you'll be well on your way to being able to fix most any CRO.

[pompeiisneaks]

Excellent, thanks!

~Phil

[Chappy425]

I know this is an old thread but I have recently been going through all of the Tek Scopes volumes on the Tek Wiki site.  I came across an article on servicing the D67 and I remembered this thread.  Not sure if it will be of any help to you or not.

Cheers
Steve

[Chris56000]

H!!

I am waiting for a parcel to be delivered that will contain an Original TQ D67 Manual, which will be scanned when I receive it!

Chris Williams

[pompeiisneaks]

So I figured I should update this thread.  I spent a lot more time reading looking over the scope etc, and started noting someone had replace a lot of the old germanium transistors with newer silicon ones and then they sold it for cheap leading me to believe someone with a lot more skill than myself realized it was beyond economic repair and gave up, thus selling it for pennies on the dollar.  So I've decided to just scrap it and move on.  Thanks for the detail by others, I'll leave this thread to the better skilled electronics wizards

~Phil