Dynatron T10a Ether Pathfinder - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

DTEC1966 · 4th Jun 2021, 3:20 pm

Well. Bought a transformer linked to a solid state rectifier, like in the mayflower, that ultimately outputs 6.5v a.c on one pair and 240v d.c on the other pair. Connected the
6.5v pair to the T10a connection for lamps and heaters, and the 240v d.c pair to the other T10a connections.( +240dc to live cable and neutral output to neutral T10a cable.

Slowly cranked up the variac and...lights slowly come on but No indication of heating of valves. ie no light/glow emitted from any valve?
Traced the 6.5 volt a.c to all of the valves and it is getting to them.

I have a 50/50 500v smoothing capacitor which I will employ if I can make any progress.

vinrads · 4th Jun 2021, 7:19 pm

It's not looking good you need to check all the valves for heater continuity, meter on ohms range, pins 4 and 5. Look for a low reading.

Mick.

DTEC1966 · 4th Jun 2021, 8:57 pm

Oh Dear

I have blown every valve. Non of them have connections across the heaters!!!!

vinrads · 5th Jun 2021, 9:10 am

All is not lost at least you haven't blown any expensive output valves, can you list all the valves you need ? I will start by looking in my stock for you.

Mick.

Station X · 5th Jun 2021, 9:22 am

Quote:

Originally Posted by DTEC1966

So some good news. Checked all the valves this morning against a working Hacker Mayflower and a Bush for the am tube. All survived!

If the heaters are now all open circuit they must have had more than 6.3V applied to them.

vinrads · 5th Jun 2021, 9:34 am

I take it you have the correct pins, looking at the pins count clockwise from the gap, good luck. Mick.

Station X · 5th Jun 2021, 9:38 am

I suppose a simple test would be to try the valves in the Mayflower again, but it would be much simpler to check with a meter.

Does the meter show a low reading when the leads are touched together on ohms range? We've been mislead by DMM readings many times in the past.

vinrads · 5th Jun 2021, 9:41 am

Good point Graham , in the event that they are all duff ,does any one know the line up , Mick.

rontech · 5th Jun 2021, 9:54 am

Quote:

Originally Posted by vinrads

good point graham , in the event that they are all duff ,does any one know the line up , mick.

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Jan Zodiac · 19th Oct 2021, 2:26 pm

Hello all.

Just came across this thread, hopefully it is not closed.

I have a T10A tuner also, whick I am planning to use in a vintage mono system. It is a separate, and of course without power supply. I did a quick check up on it, and replaced some valves that were either of a wrong type or worn out.
After that I slowly powered it up, and there is (some) life. On AM there is reception, although not so sensitive. It will of course need replacement of capacitors/resistors, and after that an alignment.
On FM it is quite sensitive, but a bit off in the discriminator.

If anyone can help with a schematic, it would be highly appreciated. I did not have any luck searching through the internet. There is not much information to be found. The tuner seems a bit complex, so a schematic would definetely be needed for restoring/alignment.

The former owner replaced a few parts, and especially one electrolytic seems a bit odd to me (47uF/250V). Also, I would like to see in detail, what the job of those small selenium "knob" recifiers is. I believe it has something to do with the indicator/discriminator. As I understand, on FM it works both as a signal level and as discriminator offset indicator. It does have some kind of a strange behaviour when tuning in on FM stations, and in general there is not much action when receiving FM stations. But with the discr. off center I guess that is what to expect. On AM it has full closing on strong stations though (my own in-house AM transmitter).

Best regards,

Jan

Synchrodyne · 19th Oct 2021, 8:49 pm

As far as I know, the service data for the Dynatron RG16, available from this site as an instant download (https://www.service-data.com/section.php/81/1/dynatron), does include a schematic and other information, including alignment instructions, for the T10a tuner.

You are right that on FM, the tuning indicator acts as combination signal strength and centre-channel device, as briefly outlined in post #19. I imagine that it would produce odd results if the discriminator alignment did not match the IF alignment.

Cheers,

Jan Zodiac · 20th Oct 2021, 6:02 pm

Thank you very much

Since I am in a EU country, instant download is not available due to the new restrictions. I emailed them, and hopefully it will be possible somehow to get the manual anyway. It would certainly be a great help.

Best regards,

Jan

4th Jun 2021, 3:20 pm	#21
DTEC1966 Triode Join Date: May 2021 Location: Swindon, Wiltshire, UK. Posts: 11	Re: Dynatron T10a Ether Pathfinder Well. Bought a transformer linked to a solid state rectifier, like in the mayflower, that ultimately outputs 6.5v a.c on one pair and 240v d.c on the other pair. Connected the 6.5v pair to the T10a connection for lamps and heaters, and the 240v d.c pair to the other T10a connections.( +240dc to live cable and neutral output to neutral T10a cable. Slowly cranked up the variac and...lights slowly come on but No indication of heating of valves. ie no light/glow emitted from any valve? Traced the 6.5 volt a.c to all of the valves and it is getting to them. I have a 50/50 500v smoothing capacitor which I will employ if I can make any progress.

4th Jun 2021, 7:19 pm	#22
vinrads Dekatron Join Date: Feb 2009 Location: Chesterfield, Derbyshire, UK. Posts: 3,760	Re: Dynatron T10a Ether Pathfinder It's not looking good you need to check all the valves for heater continuity, meter on ohms range, pins 4 and 5. Look for a low reading. Mick.

4th Jun 2021, 8:57 pm	#23
DTEC1966 Triode Join Date: May 2021 Location: Swindon, Wiltshire, UK. Posts: 11	Re: Dynatron T10a Ether Pathfinder Oh Dear I have blown every valve. Non of them have connections across the heaters!!!!

5th Jun 2021, 9:10 am	#24
vinrads Dekatron Join Date: Feb 2009 Location: Chesterfield, Derbyshire, UK. Posts: 3,760	Re: Dynatron T10a Ether Pathfinder All is not lost at least you haven't blown any expensive output valves, can you list all the valves you need ? I will start by looking in my stock for you. Mick.

5th Jun 2021, 9:34 am	#26
vinrads Dekatron Join Date: Feb 2009 Location: Chesterfield, Derbyshire, UK. Posts: 3,760	Re: Dynatron T10a Ether Pathfinder I take it you have the correct pins, looking at the pins count clockwise from the gap, good luck. Mick.

5th Jun 2021, 9:38 am	#27
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,288	Re: Dynatron T10a Ether Pathfinder I suppose a simple test would be to try the valves in the Mayflower again, but it would be much simpler to check with a meter. Does the meter show a low reading when the leads are touched together on ohms range? We've been mislead by DMM readings many times in the past. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

5th Jun 2021, 9:41 am	#28
vinrads Dekatron Join Date: Feb 2009 Location: Chesterfield, Derbyshire, UK. Posts: 3,760	Re: Dynatron T10a Ether Pathfinder Good point Graham , in the event that they are all duff ,does any one know the line up , Mick.

19th Oct 2021, 2:26 pm	#30
Jan Zodiac Pentode Join Date: Sep 2021 Location: Aabenraa, South Jutland, Denmark. Posts: 224	Re: Dynatron T10a Ether Pathfinder Hello all. Just came across this thread, hopefully it is not closed. I have a T10A tuner also, whick I am planning to use in a vintage mono system. It is a separate, and of course without power supply. I did a quick check up on it, and replaced some valves that were either of a wrong type or worn out. After that I slowly powered it up, and there is (some) life. On AM there is reception, although not so sensitive. It will of course need replacement of capacitors/resistors, and after that an alignment. On FM it is quite sensitive, but a bit off in the discriminator. If anyone can help with a schematic, it would be highly appreciated. I did not have any luck searching through the internet. There is not much information to be found. The tuner seems a bit complex, so a schematic would definetely be needed for restoring/alignment. The former owner replaced a few parts, and especially one electrolytic seems a bit odd to me (47uF/250V). Also, I would like to see in detail, what the job of those small selenium "knob" recifiers is. I believe it has something to do with the indicator/discriminator. As I understand, on FM it works both as a signal level and as discriminator offset indicator. It does have some kind of a strange behaviour when tuning in on FM stations, and in general there is not much action when receiving FM stations. But with the discr. off center I guess that is what to expect. On AM it has full closing on strong stations though (my own in-house AM transmitter). Best regards, Jan

19th Oct 2021, 8:49 pm	#31
Synchrodyne Nonode Join Date: Jan 2009 Location: Papamoa Beach, Bay of Plenty, New Zealand Posts: 2,944	Re: Dynatron T10a Ether Pathfinder As far as I know, the service data for the Dynatron RG16, available from this site as an instant download (https://www.service-data.com/section.php/81/1/dynatron), does include a schematic and other information, including alignment instructions, for the T10a tuner. You are right that on FM, the tuning indicator acts as combination signal strength and centre-channel device, as briefly outlined in post #19. I imagine that it would produce odd results if the discriminator alignment did not match the IF alignment. Cheers,

20th Oct 2021, 6:02 pm	#32
Jan Zodiac Pentode Join Date: Sep 2021 Location: Aabenraa, South Jutland, Denmark. Posts: 224	Re: Dynatron T10a Ether Pathfinder Thank you very much Since I am in a EU country, instant download is not available due to the new restrictions. I emailed them, and hopefully it will be possible somehow to get the manual anyway. It would certainly be a great help. Best regards, Jan