Help Paraset Regen not working - UK Vintage Radio Repair and Restoration Discussion Forum

NickG0HIK · 31st Dec 2015, 6:17 pm

I cannot get my Paraset reaction control to work, any tips for what is wrong?

The wiper of the Reaction control goes from Zero to about 25v

The Anode changes from about 40 to 180v with changes in reaction control.

So the valve is working okay.

Thanks

Nick

ms660 · 31st Dec 2015, 6:59 pm

If it's screen grid control it's possible but not definite that the 25 volts might not be quite enough.

If it's a Hartley configuration the cathode tap might need moving up a turn or so.

Either/or.....possibly, assuming everything else is in order.

Lawrence.

NickG0HIK · 1st Jan 2016, 7:02 pm

Thanks Lawrence,

For the helpfull pointers, in fact coming back to it after a day or two, I went straight to the problem.

Just a faulty C804 tuning cap shorting out, obviously something that I should have checked earlier, but I didn't, sometimes you can't see the wood for the trees.

Tuning quite nicely now 3.2 to 7.9 MHz, still some stuff to do on it, but it's getting there.

Nick

ms660 · 1st Jan 2016, 7:05 pm

Is that the real deal or homebrew? Whichever..it looks 1st class.

Lawrence.

NickG0HIK · 1st Jan 2016, 7:14 pm

Thanks Lawrence, no only a copy I'm afraid, I spent the last two years trawling the rallies to get as original front parts as possible.

And these holidays to build it.

Still need some better control knobs and morse key knob.

Nick

m0cemdave · 1st Jan 2016, 10:58 pm

I strongly advise keeping a close eye on the rally junk boxes for some original 10X and 10XJ crystals with frequencies in the CW bands.
Most Paraset builders use modern crystals which, being a lot smaller than the originals, suffer badly from chirp.

NickG0HIK · 2nd Jan 2016, 12:21 pm

Yes, I am of the mind the crystals is going to a problem, finding a useful frequency in 10X holder has been fruitless so far.
I think that buying some of the cheap HC-49 crystals, stuffing them into a 10X holder and constructing a transistor buffer will be the way to go.
A club member has even suggested going down the Arduino route and never again buy a crystal for a project.

31st Dec 2015, 6:17 pm	#1
NickG0HIK Hexode Join Date: Jul 2010 Location: Ireleth-in-Furness, Cumbria, UK. Posts: 286	Help Paraset Regen not working I cannot get my Paraset reaction control to work, any tips for what is wrong? The wiper of the Reaction control goes from Zero to about 25v The Anode changes from about 40 to 180v with changes in reaction control. So the valve is working okay. Thanks Nick Last edited by NickG0HIK; 31st Dec 2015 at 6:43 pm.

31st Dec 2015, 6:59 pm	#2
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Help Paraset Regen not working If it's screen grid control it's possible but not definite that the 25 volts might not be quite enough. If it's a Hartley configuration the cathode tap might need moving up a turn or so. Either/or.....possibly, assuming everything else is in order. Lawrence.

1st Jan 2016, 7:02 pm	#3
NickG0HIK Hexode Join Date: Jul 2010 Location: Ireleth-in-Furness, Cumbria, UK. Posts: 286	Re: Help Paraset Regen not working Thanks Lawrence, For the helpfull pointers, in fact coming back to it after a day or two, I went straight to the problem. Just a faulty C804 tuning cap shorting out, obviously something that I should have checked earlier, but I didn't, sometimes you can't see the wood for the trees. Tuning quite nicely now 3.2 to 7.9 MHz, still some stuff to do on it, but it's getting there. Nick Attached Thumbnails

1st Jan 2016, 7:05 pm	#4
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Help Paraset Regen not working Is that the real deal or homebrew? Whichever..it looks 1st class. Lawrence.

1st Jan 2016, 7:14 pm	#5
NickG0HIK Hexode Join Date: Jul 2010 Location: Ireleth-in-Furness, Cumbria, UK. Posts: 286	Re: Help Paraset Regen not working Thanks Lawrence, no only a copy I'm afraid, I spent the last two years trawling the rallies to get as original front parts as possible. And these holidays to build it. Still need some better control knobs and morse key knob. Nick

1st Jan 2016, 10:58 pm	#6
m0cemdave Octode Join Date: Feb 2009 Location: Bletchley, Buckinghamshire, UK. Posts: 1,223	Re: Help Paraset Regen not working I strongly advise keeping a close eye on the rally junk boxes for some original 10X and 10XJ crystals with frequencies in the CW bands. Most Paraset builders use modern crystals which, being a lot smaller than the originals, suffer badly from chirp.

2nd Jan 2016, 12:21 pm	#7
NickG0HIK Hexode Join Date: Jul 2010 Location: Ireleth-in-Furness, Cumbria, UK. Posts: 286	Re: Help Paraset Regen not working Yes, I am of the mind the crystals is going to a problem, finding a useful frequency in 10X holder has been fruitless so far. I think that buying some of the cheap HC-49 crystals, stuffing them into a 10X holder and constructing a transistor buffer will be the way to go. A club member has even suggested going down the Arduino route and never again buy a crystal for a project.