Heathkit RF-1U Sig Gen - UK Vintage Radio Repair and Restoration Discussion Forum

mastercare · 1st Mar 2017, 1:15 pm

Hi all.

Just been given one these, all valves light up voltages around 160V and 121V on smoothing cap, but no RF output on any of the bands.

I was told it was working. Are there any common faults on these?

Cheers, Paul.

Station X · 1st Mar 2017, 1:24 pm

Manual available here if you don't have it:-

http://www.vintage-radio.info/heathkit

Have you checked the other voltages?

I believe the 'U' suffix version had a 240V mains transformer for the UK market. You should be able to use the RF-1 manual for DC measurements.

Kevin Hoyland · 1st Mar 2017, 4:24 pm

Hello.

It will be the Selenium Rectifier that is U/S. I put a IN4007 Rectifier Diode in my RF-1U years ago and it is still working. The Rectifier has a resistor on each side of it R23- 47ohms/R7-2.2k. Then you will need to change all the capacitors.

Regards, Kevin

mastercare · 1st Mar 2017, 11:15 pm

Hi.

I've checked the SG on a scope, it's giving a nice sinewave, but it seems to be very low output. I will do some more readings tomorrow.

Which caps need changing? Does anyone have a list these?

If the diode was faulty would I have such high DC levels? They seem normal.

Thanks for manual I will have to study more.

Station X · 1st Mar 2017, 11:40 pm

I don't have specific knowledge of this particular SG, but in general ceramic and mica caps are OK and you would only need to replace the "tubular" caps, which presumably have a paper dielectric. See the parts list.

karesz* · 2nd Mar 2017, 2:31 am

Hello Paul,
I would chek it before output attenuator, on both sides of C25_be care pls with Uanode.
C25 can leak and R13_Level pot can be o/c...
Karl

mastercare · 2nd Mar 2017, 9:44 am

OK guys, thanks for all your input.

I'll check the paper tubular caps tomorrow. At least the scope sees some output but as I said very low.

Added problem is with my Hameg 1004-3 scope, the fly-back block on the high voltage is arcing need to find a replacement. I've put a bit resin on the block so least I can still use it. It's not been my week.

Cheers, Paul.

avocollector · 2nd Mar 2017, 11:11 am

Don't forget to check the output lead - I have a very nice solid state SG thanks to the central core of the coax lead breaking inside the output plug. The previous owner had been driven potty by the fault (worked reasonably on VHF but the lower you went the more the output dropped) so in the end he put it on auction for $10.00.

Skywave · 2nd Mar 2017, 11:22 am

Mastercare / Paul: you have a P.M.

Al.

mastercare · 2nd Mar 2017, 7:26 pm

thanks guys
turned out to be a couple suspect joints...i did a few but now its singing away into a 10 metre albrech tx im restoring after someone put it on a 24v system
thanks agn for all your help guys...
paul..

1st Mar 2017, 1:15 pm	#1
mastercare Triode Join Date: Feb 2017 Location: Bridgwater, Somerset, UK. Posts: 35	Heathkit RF-1U Sig Gen Hi all. Just been given one these, all valves light up voltages around 160V and 121V on smoothing cap, but no RF output on any of the bands. I was told it was working. Are there any common faults on these? Cheers, Paul.

1st Mar 2017, 1:24 pm	#2
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Heathkit RF-1U Sig Gen Manual available here if you don't have it:- http://www.vintage-radio.info/heathkit Have you checked the other voltages? I believe the 'U' suffix version had a 240V mains transformer for the UK market. You should be able to use the RF-1 manual for DC measurements. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

1st Mar 2017, 4:24 pm	#3
Kevin Hoyland Heptode Join Date: Feb 2009 Location: Rotherham, South Yorkshire, UK. Posts: 559	Re: Heathkit RF-1U Sig Gen Hello. It will be the Selenium Rectifier that is U/S. I put a IN4007 Rectifier Diode in my RF-1U years ago and it is still working. The Rectifier has a resistor on each side of it R23- 47ohms/R7-2.2k. Then you will need to change all the capacitors. Regards, Kevin

1st Mar 2017, 11:15 pm	#4
mastercare Triode Join Date: Feb 2017 Location: Bridgwater, Somerset, UK. Posts: 35	Re: Heathkit RF-1U Sig Gen Hi. I've checked the SG on a scope, it's giving a nice sinewave, but it seems to be very low output. I will do some more readings tomorrow. Which caps need changing? Does anyone have a list these? If the diode was faulty would I have such high DC levels? They seem normal. Thanks for manual I will have to study more.

1st Mar 2017, 11:40 pm	#5
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Heathkit RF-1U Sig Gen I don't have specific knowledge of this particular SG, but in general ceramic and mica caps are OK and you would only need to replace the "tubular" caps, which presumably have a paper dielectric. See the parts list. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

2nd Mar 2017, 2:31 am	#6
karesz* Heptode Join Date: Jun 2010 Location: Zurich, Switzerland Posts: 538	Re: Heathkit RF-1U Sig Gen Hello Paul, I would chek it before output attenuator, on both sides of C25_be care pls with Uanode. C25 can leak and R13_Level pot can be o/c... Karl

2nd Mar 2017, 9:44 am	#7
mastercare Triode Join Date: Feb 2017 Location: Bridgwater, Somerset, UK. Posts: 35	Re: Heathkit RF-1U Sig Gen OK guys, thanks for all your input. I'll check the paper tubular caps tomorrow. At least the scope sees some output but as I said very low. Added problem is with my Hameg 1004-3 scope, the fly-back block on the high voltage is arcing need to find a replacement. I've put a bit resin on the block so least I can still use it. It's not been my week. Cheers, Paul.

2nd Mar 2017, 11:11 am	#8
avocollector Heptode Join Date: Jul 2010 Location: Wellington, New Zealand. Posts: 653	Re: Heathkit RF-1U Sig Gen Don't forget to check the output lead - I have a very nice solid state SG thanks to the central core of the coax lead breaking inside the output plug. The previous owner had been driven potty by the fault (worked reasonably on VHF but the lower you went the more the output dropped) so in the end he put it on auction for $10.00.

2nd Mar 2017, 11:22 am	#9
Skywave Rest in Peace Join Date: Jun 2006 Location: Chard, South Somerset, UK. Posts: 7,457	Re: Heathkit RF-1U Sig Gen Mastercare / Paul: you have a P.M. Al.

2nd Mar 2017, 7:26 pm	#10
mastercare Triode Join Date: Feb 2017 Location: Bridgwater, Somerset, UK. Posts: 35	Re: Heathkit RF-1U Sig Gen thanks guys turned out to be a couple suspect joints...i did a few but now its singing away into a 10 metre albrech tx im restoring after someone put it on a 24v system thanks agn for all your help guys... paul..