Restoration advice on a VHF80C - UK Vintage Radio Repair and Restoration Discussion Forum

TrevorM6TSE · 23rd Feb 2009, 1:41 pm

Hi,

I'm in the middle of doing the restore of my newly aquired VHF80C and have a few questions that I wondered if you could help with?

when I picked up the radio, although it did work, there were a few "dodgy" fixes that looked to be from years past. The mains rated cap accross the switch had blown and left a black mark on the chassis. This had been replaced with a 1KV DC cap rather roughly. As the cap would then catch on the output valve a piece of old PCB had been used as a screen/heat shield to keep it off! The output transformer is an RS non original and is only screwed in on one side, and the tape output is missing.

In the first pic, I have ringed in red the caps I've changed. I've left the mains smoother as it is as it seems fine, runs cool, and there's not too much hum on the radio at all.

In the second pic I've ringed in green what I think I should replace, could you tell me if there's any more I should look to change? Also, is there any caps in the VHF frontend (ringed in blue) that I need to look at?

The set now works OK, feels a bit safer, but has a constant crackle on VHF only (it had this from the start). I've cleaned the switches and it seems to have made little difference. Sometimes the FM signal disappears completely and you just get white noise, then it comes back OK. Tapping it genally in place seems to do nothing and no amount of pressing switches etc seems to affect it. Does anyone have any experience of such a fault?

Other than that the radio is ace. Sounds brilliant and the case is excellent! I've wanted one of these for some time and it'll take pride of place as the only "retro" thing allowed in our front room!

howard · 23rd Feb 2009, 1:59 pm

Hello Trev,

I've refurbished three VHF80/VHF80C sets but I've not had your FM problem. That could be a dodgy UCC85 valve or its base so try cleaning the pins and base with a little switch cleaner and maybe swap the valve for another. It could also be a faulty waveband switch. There are capacitors in the FM tuner but I don't think any Hunts are in there so don't venture inside unless you have to !!

I usually replace the capacitor across the mains with a 275v AC X2 safety capacitor, they're small and cost under £1 apiece from Maplins, you just need to extend the leads.

Howard

Steve_P · 23rd Feb 2009, 3:23 pm

The VHF module on these does give faults. Take the module out if need be, resolder everything, clean and push the pins of the valve and the socket in slightly and this will cure most of them. And a new (or newish) UCC85. Check that the Coax is OK!

Make sure the Antenna connections are OK.

Also check the IF section. AM/FM radios such as this use different IF transformers and a different demodulator system for FM. Check here too!

They are good sets. I'm trying to get the manual up at the moment but the DVD isn't playing ball.

Cheers,

Steve P.

TrevorM6TSE · 23rd Feb 2009, 9:45 pm

Hi All,

Thanks for the updates. I've cleaned all the valve pins tonight and the sockets and the fault still remains. I think I'll have another go at the switch, then venture in to the fm frontend box. Wish me luck!

The the second picture I posted does anyone know if I've picked the right capacitors to change? One is a wax type and very gummy. One is, well not sure, and the other is a hunts brown type which is cracking.

Once I've got this all sorted, I want to drill a small hole to mount the output transformer correctly, then on to the case.

I have given in to temptation though and it's in the front room, pride of place on my partners new table

Steve_P · 23rd Feb 2009, 9:54 pm

Change the Hunts ones and that wax one. Won't do any harm and might do some good! The VHF box won't be too much trouble if you are careful. Make sure the case does not short anything out though.

Check the voltage supply to the box first though.

Cheers,

Steve P.

matthewhouse · 23rd Feb 2009, 10:39 pm

Hello, hope you enjoyed your holiday. I'm glad you are cracking on with this one. The black cap is the grid coupling cap so don't forget that one.

TrevorM6TSE · 23rd Feb 2009, 10:50 pm

Quote:

Originally Posted by matthewhouse

Hello, hope you enjoyed your holiday. I'm glad you are cracking on with this one. The black cap is the grid coupling cap so don't forget that one.

Hi Matthew,

Yes it was lovely thanks. The worst bit was actually having to leave Cornwall to come back home.

It's coming on nicely. Still haven't got to the bottom of the crackle though on FM. It's strange, seems to be worse at the 100Mhz end than at 88Mhz, so maybe it is the valve after all?

I'll get some caps ordered ASAP.

Steve_P · 23rd Feb 2009, 10:56 pm

Always swap this valve first. They aren't the most reliable valve ever made... but keep the old one. It may well be fine in another set!

Cheers,

Steve P.

TrevorM6TSE · 28th Feb 2009, 8:48 pm

Hi All,

Well, I'm getting there! All faulty or suspect Caps have been replaced and all valve pins cleaned. I've cleaned the switches again as well.

I've still got my crackle and no fm other than white noise though

It seems to come back after about 5 mins, and after 30 mins it's spot on with no crackle, so a new UCC85 is on order.

The performance of the set is great. Even with it's little internal VHF aerial it pulls in lots more signals than a modern counterpart.

I've started on the case and nearly had a nightmare. I put some T cut on and polished the side and it looked great, so did the top. Don't know if it's because the top was warm, but loads of yellow/brown stuff came off the case (didn't look like nicotine) and it went very dull, milky and rough

I put some car polish on and it was still the same. After another buff with a lot less t cut and a new colth things are back to looking good.

I'll post some pictures when done. I still need a new tuning knob though as the silver centre is missing. I've to a wanted post up.

Cheers.

23rd Feb 2009, 1:41 pm	#1
TrevorM6TSE Heptode Join Date: May 2003 Location: Old Tupton, Derbyshire, UK. Posts: 539	Restoration advice on a VHF80C Hi, I'm in the middle of doing the restore of my newly aquired VHF80C and have a few questions that I wondered if you could help with? when I picked up the radio, although it did work, there were a few "dodgy" fixes that looked to be from years past. The mains rated cap accross the switch had blown and left a black mark on the chassis. This had been replaced with a 1KV DC cap rather roughly. As the cap would then catch on the output valve a piece of old PCB had been used as a screen/heat shield to keep it off! The output transformer is an RS non original and is only screwed in on one side, and the tape output is missing. In the first pic, I have ringed in red the caps I've changed. I've left the mains smoother as it is as it seems fine, runs cool, and there's not too much hum on the radio at all. In the second pic I've ringed in green what I think I should replace, could you tell me if there's any more I should look to change? Also, is there any caps in the VHF frontend (ringed in blue) that I need to look at? The set now works OK, feels a bit safer, but has a constant crackle on VHF only (it had this from the start). I've cleaned the switches and it seems to have made little difference. Sometimes the FM signal disappears completely and you just get white noise, then it comes back OK. Tapping it genally in place seems to do nothing and no amount of pressing switches etc seems to affect it. Does anyone have any experience of such a fault? Other than that the radio is ace. Sounds brilliant and the case is excellent! I've wanted one of these for some time and it'll take pride of place as the only "retro" thing allowed in our front room! Attached Thumbnails __________________ I'd just like to say "Good luck, we're all counting on you" Last edited by TrevorM6TSE; 23rd Feb 2009 at 1:42 pm. Reason: Couldn't spell!

23rd Feb 2009, 1:59 pm	#2
howard Nonode Join Date: May 2005 Location: Godalming, Surrey, UK. Posts: 2,593	Re: Restoration advice on a VHF80C Hello Trev, I've refurbished three VHF80/VHF80C sets but I've not had your FM problem. That could be a dodgy UCC85 valve or its base so try cleaning the pins and base with a little switch cleaner and maybe swap the valve for another. It could also be a faulty waveband switch. There are capacitors in the FM tuner but I don't think any Hunts are in there so don't venture inside unless you have to !! I usually replace the capacitor across the mains with a 275v AC X2 safety capacitor, they're small and cost under £1 apiece from Maplins, you just need to extend the leads. Howard

23rd Feb 2009, 3:23 pm	#3
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Restoration advice on a VHF80C The VHF module on these does give faults. Take the module out if need be, resolder everything, clean and push the pins of the valve and the socket in slightly and this will cure most of them. And a new (or newish) UCC85. Check that the Coax is OK! Make sure the Antenna connections are OK. Also check the IF section. AM/FM radios such as this use different IF transformers and a different demodulator system for FM. Check here too! They are good sets. I'm trying to get the manual up at the moment but the DVD isn't playing ball. Cheers, Steve P. __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?

23rd Feb 2009, 9:45 pm	#4
TrevorM6TSE Heptode Join Date: May 2003 Location: Old Tupton, Derbyshire, UK. Posts: 539	Re: Restoration advice on a VHF80C Hi All, Thanks for the updates. I've cleaned all the valve pins tonight and the sockets and the fault still remains. I think I'll have another go at the switch, then venture in to the fm frontend box. Wish me luck! The the second picture I posted does anyone know if I've picked the right capacitors to change? One is a wax type and very gummy. One is, well not sure, and the other is a hunts brown type which is cracking. Once I've got this all sorted, I want to drill a small hole to mount the output transformer correctly, then on to the case. I have given in to temptation though and it's in the front room, pride of place on my partners new table __________________ I'd just like to say "Good luck, we're all counting on you"

23rd Feb 2009, 9:54 pm	#5
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Restoration advice on a VHF80C Change the Hunts ones and that wax one. Won't do any harm and might do some good! The VHF box won't be too much trouble if you are careful. Make sure the case does not short anything out though. Check the voltage supply to the box first though. Cheers, Steve P. __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?

23rd Feb 2009, 10:39 pm	#6
matthewhouse Octode Join Date: Jul 2006 Location: Willand, Devon, UK. Posts: 1,023	Re: Restoration advice on a VHF80C Hello, hope you enjoyed your holiday. I'm glad you are cracking on with this one. The black cap is the grid coupling cap so don't forget that one.

23rd Feb 2009, 10:56 pm	#8
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Restoration advice on a VHF80C Always swap this valve first. They aren't the most reliable valve ever made... but keep the old one. It may well be fine in another set! Cheers, Steve P. __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?

28th Feb 2009, 8:48 pm	#9
TrevorM6TSE Heptode Join Date: May 2003 Location: Old Tupton, Derbyshire, UK. Posts: 539	Re: Restoration advice on a VHF80C Hi All, Well, I'm getting there! All faulty or suspect Caps have been replaced and all valve pins cleaned. I've cleaned the switches again as well. I've still got my crackle and no fm other than white noise though It seems to come back after about 5 mins, and after 30 mins it's spot on with no crackle, so a new UCC85 is on order. The performance of the set is great. Even with it's little internal VHF aerial it pulls in lots more signals than a modern counterpart. I've started on the case and nearly had a nightmare. I put some T cut on and polished the side and it looked great, so did the top. Don't know if it's because the top was warm, but loads of yellow/brown stuff came off the case (didn't look like nicotine) and it went very dull, milky and rough I put some car polish on and it was still the same. After another buff with a lot less t cut and a new colth things are back to looking good. I'll post some pictures when done. I still need a new tuning knob though as the silver centre is missing. I've to a wanted post up. Cheers. __________________ I'd just like to say "Good luck, we're all counting on you"