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Old 11-06-2016, 01:02 PM   #16
Guglielmo Terra
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Very good document, very clear, thanks.
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Old 11-20-2016, 04:26 AM   #17
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Hi, I have another request for help for the restoration of my 80.W.S.
They lack the resistors behind the voltmeter and unfortunately the manual is not marked values. You know the vaore of them? Or if you have a picture where you see the values?
Thank you .
Regards.
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Old 11-23-2017, 11:17 AM   #18
Guglielmo Terra
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Still a question about 80w.s.
The voltage divider resistors that power the RL12P35 tubes heat up a lot.
So much so that you can not touch the case.
It's normal?
Someone knows the value of resistances n.22,23,18 and 19 (ohms and watts)?
Many thanks
Regards
Riccardo.
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Old 11-23-2017, 01:10 PM   #19
Funksammler
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I have two 80W.S waiting to be restored later this winter (need to finish some other stuff first). If it can wait I can probably answer your questions once I get going on my 80 W.S projects, happy to compare notes...

regards,

Funksammler
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Old 11-24-2017, 08:48 AM   #20
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Ok !
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Old 12-17-2017, 10:55 AM   #21
Funksammler
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Quote:
Originally Posted by Guglielmo Terra View Post
Still a question about 80w.s.
The voltage divider resistors that power the RL12P35 tubes heat up a lot.
So much so that you can not touch the case.
It's normal?
Someone knows the value of resistances n.22,23,18 and 19 (ohms and watts)?
Many thanks
Regards
Riccardo.

Well, I just finished restoring the first 80 W.S.a and I can confirm that the resistors get pretty hot! The 800V anode Voltage has to be reduced somewhat by a divider for the RL12P2000's, a quick calculation shows that these resistors have to dissipate approximately 15 Watt together. The voltage divider for the grid voltage of the power stage uses even lower value resistors, these dissipate over 46 Watt . So together these few resistor dissipate nearly as much as the HF output of the transmitter!

Quote:
Originally Posted by Guglielmo Terra View Post
Hi, I have another request for help for the restoration of my 80.W.S.
They lack the resistors behind the voltmeter and unfortunately the manual is not marked values. You know the vaore of them? Or if you have a picture where you see the values?
These are three resistors of 1Meg each making a 1/3 voltage divider. The divider relies on the (relatively low) impedance of the the measuring instrument to get the voltage down to 4 Volt at the HV terminal of the instrument. I had to repair this divider and I was a bit suspicious so I tested it first with a 1 Meg potentiometer in series with the instrument, only after I found that I could safely turn the potmeter to zero without blowing up the voltmeter did I solder in the instrument permanently...

regards,

Funksammler

Last edited by Funksammler; 12-17-2017 at 11:19 AM.
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Old 12-17-2017, 11:21 AM   #22
Funksammler
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Quote:
Originally Posted by Guglielmo Terra View Post
Still a question about 80w.s.
The voltage divider resistors that power the RL12P35 tubes heat up a lot.
So much so that you can not touch the case.
It's normal?
Someone knows the value of resistances n.22,23,18 and 19 (ohms and watts)?
Many thanks
Regards
Riccardo.
I can't read any values on the resistors itself so I will have to calculate them

18 and 19 are 16 KOhm
22 and 23 are 10 KOhm
(97 and 99 are 1.5 kOhm)

So the Total resistance of the divider is 27.5 kOhm. At a voltage of 800 Volt there will be a current of 29 mAmp. so 18 and 19 dissipate about 14 Watt, 22 and 23 dissipate about 8.5 Watt. So to be on the safe side I would say

18 and 19: 16 kOhm 20 Watt
22 and 23: 10 kOhm 10 Watt

regards,

Funksammler
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Old 12-18-2017, 12:52 PM   #23
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Got the second 80 W.S.a up and running as well. Strangely one of the 1 Mohm resistors of the instrument voltage divider was missing, There was no evidence of any de-soldering, it looked like it just fell off due to a weak soldering link. With a NOS resistor soldered in place, the instrument is working correctly again for HV.

I encountered another weird issue, the antenna could not be tuned correctly above 2.5 Mhz; at 3 Mhz there was virtually no power output. I had noticed that compared to the first 80 W.S.a I restored, the settings of the "course" antenna tuning switch were two steps higher across the board, so I suspected something wrong with the capacitors in the circuit. I measured and checked everything and everything seemed to be correct, no damaged components could be found and all the soldering connections were original, the transmitter looks like it has never been messed with.

The antenna tuning goniometer can turn freely over 360 degrees, however the control knob limits the travel to 180 degrees. So I removed the knob, turned the goniometer 180 degrees and refitted the knob. After this the transmitter worked fine up to the maximum frequency.

I suspect that the transmitter left the factory with the goniometer inverted, either by mistake or as a deliberate act of sabotage. It would have been difficult to spot in during final inspection (unless they tested the transmitter at all its frequencies) and would have been a tricky fault to diagnose in the field. So just be aware that there is a right and a wrong way to fit the goniometer knob....

regards,

Funksammler
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Goniometer inverted
Old 12-19-2017, 03:02 AM   #24
LA6NCA
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Default Goniometer inverted

Thank you for this information Funksamler.

I'll start working on my other 80WSa now after Christmas.
This error is quick to do yourself.
I have to take care of this.
Is this an error that can be done on other radios too.
Like 15WSEa?

Regards LA6NCA
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Old 12-19-2017, 03:10 AM   #25
Guglielmo Terra
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Thanks for the precious and clear information. It will seem strange to you, but also in mine there was no resistance from the voltage divider of the instrument. It had fallen into the chassis and seemed not soldered !!
Another strange thing: in my manual D978 / 1 the value of the resistance R23 is 16Kohm?
Instead of 10Kohm.
Best wishes for Happy Holidays.


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Old 12-19-2017, 10:53 AM   #26
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hello
FS about the very good description of tuning antenna system fault.
In my mind a goniometer is a device for measuring angles
you have optical goniometer or sitometre
for a moving coil , variometer , at school we use variometer term
if you consider the coil is moving an angle i guess it 's same
or is it language barrier ? or other explanation
pierre
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Old 12-19-2017, 12:07 PM   #27
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Goniometer is probably an old school term not used very much today, I guess it is what I grew up with. In French the term Gonio is also used for a DF antenna so the terms tends to stick... For me a Variometer is more of an aircraft instrument measuring rate of climb. I guess the Germans called it a variometer, so I will try and use that term the next time.

regards,

Funksammler
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Old 12-20-2017, 07:59 AM   #28
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I must admit, I read over the difference in resistors 22 and 23 as it makes no sense for them to be different. They are exactly the same size and type:



I decided to measure them and I got very inconsistent measurements, from about 5K to 8K. My final measurements seem to settle on 5.1K each, so what is going on? I remembered our conversation about them getting very hot, so I decided to measure them again after operating the transmitter for a couple of minutes. This time I measured them at 9.3K. So the values in the table seem to apply to operating temperature, when cold the resistance is about halved. In any case, I measure 22 and 23 at the same value, so I assume there is a typo in the manual and they should both be 10K.

It was a good thing I checked the resistors. I was having a strange problem where the power of the transmitter sometimes suddenly dropped off. I noticed that the two middle resistors (18 and 19) were very close together, in fact the metal clamps on the resistors were just about touching. I moved the two resistors apart and my power drop-off problem appears to be cured. When the two resistors touched, the screen grid voltages of both output valves became connected, knocking the power stage out of oscillation.

The final job I had to do was to free up the trimmer capacitors for the master oscillator. The three trimmers (one for each frequency band) sit in an alloy casting on the master oscillator module. The assembly can just about be removed from the transmitter without having to dismantle the master oscillator unit, but it requires the oscillator coils to be loosened and pushed to the side to create enough space....

This is the trimmer assembly:



The three trimmers can now be removed:



People prefer different methods for freeing up seized trimmer capacitors, I prefer a good soak in penetrating oil first. Never try to loosen a trimmer by turning with a screwdriver, all you do is break the soldering bond between the screw and the top plate. The turning force has to be applied to the circumference of the top disk, I prefer to use a tie-wrap to create grip:



When the capacitors turn freely they can be rinsed clean with contact spray and they must be left to dry. After this the trimmers are fitted back into the assembly and the transmitter can be reassembled. A lot of work for such a small but common problem!

regards,

Funksammler

Quote:
Originally Posted by Guglielmo Terra View Post
Thanks for the precious and clear information. It will seem strange to you, but also in mine there was no resistance from the voltage divider of the instrument. It had fallen into the chassis and seemed not soldered !!
Another strange thing: in my manual D978 / 1 the value of the resistance R23 is 16Kohm?
Instead of 10Kohm.
Best wishes for Happy Holidays.


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Old 12-20-2017, 08:57 AM   #29
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Finally, a picture of the two beasts together. Both are from 1944, the bottom one S/N 135673, the top one S/N 136457. So this provides a nice comparison with Guglielmo's 1941 example:



Somewhere between these two serial number a number of production changes were made:

- Colour change of the faceplate from grey to tan
- Use of "einheits" instruments

Also interesting is that the tan 80 W.S.a has grown a protrusion underneath the frequency scale forcing the placement of the handle to the right. Closer inspection revealed axle of the tuning mechanism on the later transmitter protrudes outside the faceplate.

Some of you may remember the discussion we had about late war 30 W.S.a transmitters, in particular the circular channel preselector ring that can be found on some 30 W.S.a''s: http://www.wehrmacht-awards.com/foru...light=30+W.S.a

It shows that the changed axle design was also used on the 80 W.S.a except they did not fit the preselector ring. It provides a proof that both types of transmitters were built using the same parts bin and more proof that the preselector ring for the 30 W.S.a was introduced somewhere in 1944.

regards,

Funksammler
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Old 12-20-2017, 10:12 AM   #30
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I still was not 100% happy with the antenna tuning variometer, I still had a small blackspot right at the bottom of the frequency range. Good thing I had the 2 transmitters side by side, so I could do a visual inspection to see if there were any differences. It turned out the that variometer was 90 degrees (rather than 180) out of alignment. This is even stranger as the control knob only fits in two ways on the axle stub 180 degrees apart. Fortunately you can change the position of the needle of the control knob by 90 degrees (remove two screws that hold the needle, change and screw down again), so now finally can I turn the variometer over the correct range. A very strange fault indeed...

regards,

Funksammler
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