Racal RA.17 MKII Kc/s VFO overhaul... - UK Vintage Radio Repair and Restoration Discussion Forum

Racalfanatic · 18th Aug 2007, 1:16 pm

Hi All,
I'm new on here but not new to vintage radio

I recently purchased a new second VFO for one of my RA.17s and I am going to re-lubricate it and fit it this weekend.
The VFO is new old stock and the inspection tag is dated April 1967, just 2 weeks before I was born. The VFO came in a thick polythens sealed bag with a 16oz bag of silica gel to keep the moisture out. I am going to leave it alone electrically despite it being fitted with Hunts decoupling capacitors. However, I shall check all of the resistors and replace any that are significantly out of tolerance. Where possible, I shall re-lubricate the moving parts paying particular attention to the worm drive, which I have the correct lubricant for.

As I have already stated, the VFO arrived in a sealed bag but it was covered in insulation tape which, when removed, left a nasty sticky residue which I have now removed.

I have four RA.17s, three are MKIIs and one is a 17L or MKIII. Two "live" in my loft and the other two are in regular use, one of them on a daily basis.

Please see the pictures below.
I shall post more photos of the job being done soon.

Cheers,
Ian G1DRP

http://img.photobucket.com/albums/v2...9/DSCN0318.jpg
http://img.photobucket.com/albums/v2...9/DSCN0319.jpg
http://img.photobucket.com/albums/v2...9/DSCN0323.jpg

Skywave · 18th Aug 2007, 4:43 pm

Hi.

Despite what is said about Hunts capacitors, it has been my experience that the types fitted in RA-17's rarely give trouble.
Good luck with it! - I look forward to seeing photos as the work progresses.
- From another RA-17 enthusiast.

Al / Skywave

Racalfanatic · 18th Aug 2007, 5:34 pm

I have to agree with you on this point. I have re-capped one of my RA.17s but left the others alone. The re-capped one gets lots of use, I switch it on at 17:30 and then off again at 23:30 on weekdays and I leave it on all weekend. It never lets me down and, because I let it warm up for a good few hours before I actually listen to it, it doesn't drift.
I've owned many different HF receivers but nothing compares with the RA.17 in my humble opinion.

Cheers,
Ian G1DRP

XTC · 18th Aug 2007, 9:36 pm

I've two and a half RA17s, an MkII an RA17L and an RA17L I bought for spares (minus mains transformers and choke). The scrapper earned its crust when the 2nd VFO in the RA17L died and I had the luxury of being able to swap a spare in and have everything spring back to life. It wasn't quite a straight swap because the film roller was seized and had a step worn, so I had to have a new one machined up. The original 2nd VFO had a resistor fail and wiring was dodgy, and that whole area of the set was so much of a hassle to get to that there was no point in replacing the resistor without doing the rest.

If your VFO came sealed in plastic with dessicant, you shouldn't have any problems.

What's the correct lubricant for the worm drive? I've used a touch of MS grease.

They're great sets and the only valve set compared to them is the Collins R390A. I gather that in the US the Collins is held in the same regard as the RA17 is here. It would be interesting to try the two properly peaked up, side to side.

There is a Racal 19" rack for RA17s and accessory units. Very nice if you can get one and your floor can take the strain.

Anyway, it's always good to hear from another Racal enthusiast.

Pete.

Skywave · 19th Aug 2007, 12:39 pm

Quote:

Originally Posted by Racalfanatic

I've owned many different HF receivers but nothing compares with the RA.17 in my humble opinion.
Ian G1DRP

Exactly. I've said that myself, many times.

Al / Skywave.

Racalfanatic · 19th Aug 2007, 2:47 pm

Quote:

Originally Posted by XTC

What's the correct lubricant for the worm drive? I've used a touch of MS grease.

Pete.

Hi Pete,

MS grease if absolutely fine but I prefer Moebius 8201 which is similar but a bit thinner and is meant for horological purposes. For everything else, I use Moebius D5 which is a mineral lubricant intended for load bearing pivots in watch movements.

Thanks for your interesting post. I'll be back with some photos later.

Ian G1DRP

Racalfanatic · 19th Aug 2007, 5:54 pm

It's now fitted and working!

I re-lubricated exerything first though.
http://img.photobucket.com/albums/v2...h_DSCN0326.jpg
http://img.photobucket.com/albums/v2...h_DSCN0325.jpg
http://img.photobucket.com/albums/v2...h_DSCN0324.jpg
http://img.photobucket.com/albums/v2...h_DSCN0329.jpg
http://img.photobucket.com/albums/v2...h_DSCN0328.jpg

Racalfanatic · 19th Aug 2007, 6:02 pm

This is a view of the radio before work commenced.
http://img.photobucket.com/albums/v2...h_DSCN0331.jpg
Now shown with the 100KHz marker oscillator removed. It plugs into the side of the VFO by means of an octal scocket.The 100KHz is derived from the radio's 1MHz crystal oscillator.
http://img.photobucket.com/albums/v2...h_DSCN0332.jpg
Now the VFO is disconnected from the other modules.
http://img.photobucket.com/albums/v2...h_DSCN0333.jpg
The bottom plate has to be removed so that the power connections can be removed from the VFO.
http://img.photobucket.com/albums/v2...h_DSCN0334.jpg

Racalfanatic · 19th Aug 2007, 6:07 pm

As you can see, the power supply resistors have been upgraded at some time in the past.
http://img.photobucket.com/albums/v2...h_DSCN0338.jpg
Just look at the quality of those gears. The IF filters are switched here.
http://img.photobucket.com/albums/v2...h_DSCN0335.jpg
I replaced a few resistors and decoupling caps earlier in the year. This is the IF strip power rail etc..
http://img.photobucket.com/albums/v2...h_DSCN0336.jpg

Racalfanatic · 19th Aug 2007, 6:13 pm

Here are the three wires which need to be de-soldered before the VFO can be withdrawn.
http://img.photobucket.com/albums/v2...h_DSCN0339.jpg
Next, remove the front panel.
http://img.photobucket.com/albums/v2...h_DSCN0342.jpg
Now, remove the Mc/s dial.
http://img.photobucket.com/albums/v2...h_DSCN0343.jpg
The VFO cover has to be removed to reveal one of the securing screws.
http://img.photobucket.com/albums/v2...h_DSCN0344.jpg

Racalfanatic · 19th Aug 2007, 6:21 pm

There are three screws securing the VFO to the main chassis. They are pretty obvious once the RX is in bits.
The VFO can now be carefully withdrawn from the chassis.
http://img.photobucket.com/albums/v2...h_DSCN0345.jpg
Re-fitting is the a piece of cake!
http://img.photobucket.com/albums/v2...h_DSCN0346.jpg
The finished item minus the top cover.
http://img.photobucket.com/albums/v2...h_DSCN0347.jpg
The last job is to ensure that the film scale is correctly lined up.
This is relatively easy and the marker oscillator really helps.

Hope you enjoyed this small photo journey around my 1960 Racal RA.17 MKII.

Cheers,
Ian G1DRP

18th Aug 2007, 1:16 pm	#1
Racalfanatic Retired Dormant Member Join Date: Aug 2007 Location: Stoke-on-Trent, Staffordshire, UK. Posts: 105	Racal RA.17 MKII Kc/s VFO overhaul... Hi All, I'm new on here but not new to vintage radio I recently purchased a new second VFO for one of my RA.17s and I am going to re-lubricate it and fit it this weekend. The VFO is new old stock and the inspection tag is dated April 1967, just 2 weeks before I was born. The VFO came in a thick polythens sealed bag with a 16oz bag of silica gel to keep the moisture out. I am going to leave it alone electrically despite it being fitted with Hunts decoupling capacitors. However, I shall check all of the resistors and replace any that are significantly out of tolerance. Where possible, I shall re-lubricate the moving parts paying particular attention to the worm drive, which I have the correct lubricant for. As I have already stated, the VFO arrived in a sealed bag but it was covered in insulation tape which, when removed, left a nasty sticky residue which I have now removed. I have four RA.17s, three are MKIIs and one is a 17L or MKIII. Two "live" in my loft and the other two are in regular use, one of them on a daily basis. Please see the pictures below. I shall post more photos of the job being done soon. Cheers, Ian G1DRP http://img.photobucket.com/albums/v2...9/DSCN0318.jpg http://img.photobucket.com/albums/v2...9/DSCN0319.jpg http://img.photobucket.com/albums/v2...9/DSCN0323.jpg

18th Aug 2007, 4:43 pm	#2
Skywave Rest in Peace Join Date: Jun 2006 Location: Chard, South Somerset, UK. Posts: 7,457	Re: Racal RA.17 MKII Kc/s VFO overhaul... Hi. Despite what is said about Hunts capacitors, it has been my experience that the types fitted in RA-17's rarely give trouble. Good luck with it! - I look forward to seeing photos as the work progresses. - From another RA-17 enthusiast. Al / Skywave

18th Aug 2007, 5:34 pm	#3
Racalfanatic Retired Dormant Member Join Date: Aug 2007 Location: Stoke-on-Trent, Staffordshire, UK. Posts: 105	Re: Racal RA.17 MKII Kc/s VFO overhaul... I have to agree with you on this point. I have re-capped one of my RA.17s but left the others alone. The re-capped one gets lots of use, I switch it on at 17:30 and then off again at 23:30 on weekdays and I leave it on all weekend. It never lets me down and, because I let it warm up for a good few hours before I actually listen to it, it doesn't drift. I've owned many different HF receivers but nothing compares with the RA.17 in my humble opinion. Cheers, Ian G1DRP

18th Aug 2007, 9:36 pm	#4
XTC Retired Dormant Member Join Date: Oct 2004 Location: Bristol, UK. Posts: 837	Re: Racal RA.17 MKII Kc/s VFO overhaul... I've two and a half RA17s, an MkII an RA17L and an RA17L I bought for spares (minus mains transformers and choke). The scrapper earned its crust when the 2nd VFO in the RA17L died and I had the luxury of being able to swap a spare in and have everything spring back to life. It wasn't quite a straight swap because the film roller was seized and had a step worn, so I had to have a new one machined up. The original 2nd VFO had a resistor fail and wiring was dodgy, and that whole area of the set was so much of a hassle to get to that there was no point in replacing the resistor without doing the rest. If your VFO came sealed in plastic with dessicant, you shouldn't have any problems. What's the correct lubricant for the worm drive? I've used a touch of MS grease. They're great sets and the only valve set compared to them is the Collins R390A. I gather that in the US the Collins is held in the same regard as the RA17 is here. It would be interesting to try the two properly peaked up, side to side. There is a Racal 19" rack for RA17s and accessory units. Very nice if you can get one and your floor can take the strain. Anyway, it's always good to hear from another Racal enthusiast. Pete. Last edited by Station X; 18th Aug 2007 at 10:45 pm. Reason: Line wrap fixed.

19th Aug 2007, 5:54 pm	#7
Racalfanatic Retired Dormant Member Join Date: Aug 2007 Location: Stoke-on-Trent, Staffordshire, UK. Posts: 105	Re: Racal RA.17 MKII Kc/s VFO overhaul... It's now fitted and working! I re-lubricated exerything first though. http://img.photobucket.com/albums/v2...h_DSCN0326.jpg http://img.photobucket.com/albums/v2...h_DSCN0325.jpg http://img.photobucket.com/albums/v2...h_DSCN0324.jpg http://img.photobucket.com/albums/v2...h_DSCN0329.jpg http://img.photobucket.com/albums/v2...h_DSCN0328.jpg

19th Aug 2007, 6:02 pm	#8
Racalfanatic Retired Dormant Member Join Date: Aug 2007 Location: Stoke-on-Trent, Staffordshire, UK. Posts: 105	Re: Racal RA.17 MKII Kc/s VFO overhaul... This is a view of the radio before work commenced. http://img.photobucket.com/albums/v2...h_DSCN0331.jpg Now shown with the 100KHz marker oscillator removed. It plugs into the side of the VFO by means of an octal scocket.The 100KHz is derived from the radio's 1MHz crystal oscillator. http://img.photobucket.com/albums/v2...h_DSCN0332.jpg Now the VFO is disconnected from the other modules. http://img.photobucket.com/albums/v2...h_DSCN0333.jpg The bottom plate has to be removed so that the power connections can be removed from the VFO. http://img.photobucket.com/albums/v2...h_DSCN0334.jpg

19th Aug 2007, 6:07 pm	#9
Racalfanatic Retired Dormant Member Join Date: Aug 2007 Location: Stoke-on-Trent, Staffordshire, UK. Posts: 105	Re: Racal RA.17 MKII Kc/s VFO overhaul... As you can see, the power supply resistors have been upgraded at some time in the past. http://img.photobucket.com/albums/v2...h_DSCN0338.jpg Just look at the quality of those gears. The IF filters are switched here. http://img.photobucket.com/albums/v2...h_DSCN0335.jpg I replaced a few resistors and decoupling caps earlier in the year. This is the IF strip power rail etc.. http://img.photobucket.com/albums/v2...h_DSCN0336.jpg

19th Aug 2007, 6:13 pm	#10
Racalfanatic Retired Dormant Member Join Date: Aug 2007 Location: Stoke-on-Trent, Staffordshire, UK. Posts: 105	Re: Racal RA.17 MKII Kc/s VFO overhaul... Here are the three wires which need to be de-soldered before the VFO can be withdrawn. http://img.photobucket.com/albums/v2...h_DSCN0339.jpg Next, remove the front panel. http://img.photobucket.com/albums/v2...h_DSCN0342.jpg Now, remove the Mc/s dial. http://img.photobucket.com/albums/v2...h_DSCN0343.jpg The VFO cover has to be removed to reveal one of the securing screws. http://img.photobucket.com/albums/v2...h_DSCN0344.jpg

19th Aug 2007, 6:21 pm	#11
Racalfanatic Retired Dormant Member Join Date: Aug 2007 Location: Stoke-on-Trent, Staffordshire, UK. Posts: 105	Re: Racal RA.17 MKII Kc/s VFO overhaul... There are three screws securing the VFO to the main chassis. They are pretty obvious once the RX is in bits. The VFO can now be carefully withdrawn from the chassis. http://img.photobucket.com/albums/v2...h_DSCN0345.jpg Re-fitting is the a piece of cake! http://img.photobucket.com/albums/v2...h_DSCN0346.jpg The finished item minus the top cover. http://img.photobucket.com/albums/v2...h_DSCN0347.jpg The last job is to ensure that the film scale is correctly lined up. This is relatively easy and the marker oscillator really helps. Hope you enjoyed this small photo journey around my 1960 Racal RA.17 MKII. Cheers, Ian G1DRP