Talyvel 1/2 service manual?

[darylbane]

I recently picked up a Talyvel 1 electronic level. No real need for it other than lust. It was in excellent condition, but apparently had been placed out of service in 1975. After applying correct voltage to the unit as the original mercury batteries were long dead, a number of electronic issues surfaced which I attributed to the vintage components. The actual circuitry is nothing more than a simple transistor amplifier but a bit more challenging to a non electronics person(me). Even though Taylor-Hobson still exists, and will gladly supply a users manual, acquiring a suitable service manual (schematic)seems to be impossible. This unit is probably out of the realm of most of the members here, but you never know what information can surface in a forum such as this.

[nickel-city-fab]

I recently picked up a Talyvel 1 electronic level. No real need for it other than lust. It was in excellent condition, but apparently had been placed out of service in 1975. After applying correct voltage to the unit as the original mercury batteries were long dead, a number of electronic issues surfaced which I attributed to the vintage components. The actual circuitry is nothing more than a simple transistor amplifier but a bit more challenging to a non electronics person(me). Even though Taylor-Hobson still exists, and will gladly supply a users manual, acquiring a suitable service manual (schematic)seems to be impossible. This unit is probably out of the realm of most of the members here, but you never know what information can surface in a forum such as this.

I can recommend to check on the eevblog forum: https://www.eevblog.com/forum/
They have several sub-forums where it may be appropriate to post a "help wanted" request.
That is where the electronics pros hang out and repair test equipment as a business.
Chances are very good that you can find someone there, who is willing to take it on.
Many of their members also have access to the factory schematics and repair info, etc.

[old mart]

That's a handy link to bookmark, NSF, thanks. Here's another that might be useful.

https://www.badcaps.net/forum/

[darylbane]

Many Thanks, will check it out. I was able to replace the old electrolytic capacitors, which unfortunately didn't fix it ,although it does now seem to be alittle more stable. But when gently moving around the transistors to get numbers, one literally fell apart...hmmm . So I was able to order a replacement which has not yet arrived. We'll see. Thanks again.

[JRouche]

acquiring a suitable service manual (schematic.

In my travels of trying to repair anything these days is a Service manual is next to impossible to get near.

I have needed schematics that was a no go, and ended up tracing the system down to as far as I could and drawing my own diagrams. Tracing means all signals at all points with a meter, And when off all continuity numbers.

You can trace the path that way with most boards, did it with a big screen TV

I did need the microscope camera for that fix though. My smallest fix yet. Stupid right.. That was 13 years ago..

Fix, dont replace IMO.... (yes, TV still works). JR

[JRouche]

Many Thanks, will check it out. I was able to replace the old electrolytic capacitors, which unfortunately didn't fix it ,although it does now seem to be alittle more stable. But when gently moving around the transistors to get numbers, one literally fell apart...hmmm . So I was able to order a replacement which has not yet arrived. We'll see. Thanks again.

I like your approach. Troubleshooting has to start a some point. Usually its sight or smell and feel.

Yours was the best and most common. Get knowledge as to how to go about fixing it.


JR

[djc]

Have a look here, starting at post #69

https://www.practicalmachinist.com/vb/machine-reconditioning-scraping-and-inspection/building-differential-electronic-levels-291287/index4.html

[darylbane]

Yes, I have been in contact with three of those posters. One was able to send me a Service manual for a much later unit, which was quite useful in dealing with the read head. Seems the internals although alittle different, still utilized the same design This was very helpful in checking adjustment of this unit. I now know what the parts do.