This guide was put together for another member but I feel that I should post it for the benefit of all.

The Körting (pronounced Kerting, just ask any German) had an annoying problem of intermittent shutdown, and because it used unusual circuitry many found it difficult to fix. Just use the following text. It should help.

The most important thing, and the starting point is the voltage at the cathode of D1103 on the
R board It must be 42V when the set is running. If it is anything else, even close to 42V you are just buying yourself trouble.

If you can not get the set to turn on, try to short together pins 10 and 11 of the R board This will cause the set to run at a reduced voltage to the output stage. Still no luck, short together pins A and short together pins B on the R board.



Don't forget to try the obvious things like disconnecting the input to the trippler, measuring for shorted scan thyristor, blown fuses etc. also check R1031 in the bottom of the trippler.

Some of the things I have listed here on my “Fault Sheet”, are
1. Tracking on side of the trippler and/or around the ultor.
2. Loose core of the commutation transformer. Causes the EHT to rise, also R1109 not to set.
3. I have also had IS 1101 fail (12V regulator) For some reason, in the early days, these three terminal regulators were common offenders, in all brands of sets.
4. Most important! For any intermittent shut-down which can not be determined, replace both thyristors ITD1001and ITD 1002. This will save you much heartache. They do fail, and you will not be able to measure them.
5. If R606 is frying or open, suspect C606b to be faulty.
6. Failure of one or more of the Polycarbonate Block type capacitors in the horizontal output stage. These are low-power factor caps, don't try to use anything else as replacements. They will heat-up and fail within a minute.
The faulty cap/s will usually have bulging on the sides of the cap.

The really early versions were fitted with a half wave rectification N board. These were quickly changed to a full wave rectification board.

Note. The set must shut-down whenever pins S on the N board are shorted together. Check this when the set is hot. Change TH601 if it does not shut-down.

I have only once had a faulty Horizontal output transformer in a thyristor output stage set. That was caused by a cable too near the transformer causing a corona spray that burnt through the transformer. That is not to say that at their advanced age, and doubtful storage conditions, a transformer could be at fault, it is just that I have never seen one, just fail.

Again. Once you have the set working on reduced voltage, (overrides enabled) switch off, remove the overrides, switch on again and adjust for 42V at at the cathode of D1103.

This information should be enough to enable anyone to get their Körting 56 696 20 inch PIL
55636 20 inch PIL
56 791 27 inch Delta set running.


Wayne

Wish I could see one of these sets 'in the flesh '. Seems like they're a unique design.

Dear Zenith.

I have hunted around and found the following pictures. The chassis drops down for servicing and the modules can be inserted on the rear of the board for voltage/waveform measurements.

Please note. The picture of the set from the front was not supplied my me but by another member.

After all these years I still remember these sets fondly, except for the mongrel 27" delta one that had an amazingly difficult vertical fault!

I hear you ask. "What can be so difficult about a vertical fault?"

Wayne

Here's a picture of the chassis from the set in the last picture of the previous post.

This set was rescued after sitting in the weather for a few days (or weeks?) so it needed a good clean when this picture was taken.

They must have been fairly decent sets, this particular set worked despite the weathering and only needed the focus control to be cleaned to restore a decent picture.