An unloved Hacker Herald VHF restored - UK Vintage Radio Repair and Restoration Discussion Forum

Superhet Si · 24th Sep 2006, 2:16 pm

Last week I won a Red Hacker Herald RP37A sold as non working with a suspect power switch.
When the set arrived I could see straight away this radio was in need of some serious work.
The grill was stoved in an badly corroded, the volume pot/switch was unserviceable, the trim on the handle looked like it had been stuck on with no nails and the rexine was very saggy on the front. It did however have a good aerial and a Elac speaker fitted, which I have never seen on these sets before.
So I set about stripping the chassis out and removing the volume pot. Once I had the old pot out I fitted one from a donor Rp35.

Time to see if the thing would power up. I wired an ammeter is series with the battery lead and powered the radio up out of chassis. All I was rewarded with was a loud switch on thump and no sound. At this point the current consumption was ~30mA, and although not very high, is to much for this radio in an idle condition.
Looking around the Amp board soon found a shorted AC176 NPN output transistor. Great

No spare transistors

So the Rp35 again gave up it's working amp for the Rp37A.
Upon switch on this time the radio showed some signs of life but did seem very insensitive. I thought at this point I would come back to this problem a bit later.

Next the Front panel of the set was removed and the rexine peeled off the corners of the cabinet. The Front grill was removed and the dent pushed out better than I thought. Once all the rexine was lifted, I used a stiff brush to remove add the loose foam remaining between the cabinet and the rexine.
I then cut up sections off high temperature pipe insulation to replace the space where the foam one belonged. Then it was a case of Evosticking the rexine down to the cabinet while stretching it to remove any creases. Once the rexine was dry the front of the set looked a million times better.
I rebuilt the cabinet and replaced a few corroded battery stays along the way
and was ready to sort out the lack of sensitivity.

This later VHF set uses a different tuner board (type T309) and although it is mentioned in the service data, there is no alignment instructions.
With a bit of working out, and the help of the circuit I soon found where the oscillator core was. Radio 2 was about 1 MHz off tune according to the scale calibration (which was checked before proceeding) so a tweak of the core bought it back where it was meant to be. Then the padder was tweaked to get Kiss FM to 100 MHz. A bit of time was taken to get the scale linearity correct but it soon was spot on. Still very insensitive

Setting the set to 90Mhz I peaked the two cores for max output through the speaker. Then I went to 98Mhz and did the two remaining trimmers.
Now I set was how it should be, sensitive and clear all the way through the range.

Considering I was thinking of using this set for spares I am very pleased with the results.
I have noticed a few things along the way though.
1 Brass grills are far weaker than the steel equivalents.
2 VHF Hackers oscillators always seem to drift with age.

If you would like to see the results and the foam padding I used, follow the link below to the Hacker picture gallery.

howard · 24th Sep 2006, 4:38 pm

Hello Simon,

I was offered one of these recently and turned it down cos its brightwork was badly deteriorated (plus it was missing its aerial). I've seen these red Heralds come and go on that well known online fleamarket and none have looked in particularly good condition

I daresay there are one or two nice examples around and I hope to find one cos these are really nice looking Hackers. I saw your restoration of this one on your website, I haven't 'responged' a Hacker cos I haven't found any suitable sponge to date so I have two or three to do when I eventually find some.

Well done, nice to see one of these pretty radios working well and looking smart again

Howard

GJR 11L · 24th Sep 2006, 5:59 pm

Hi Simon,
I found this particularly interesting as I've never actually met a Herald or Sovereign with a steel grille, all of my RP18s/25s/30s/35s/37s/37As etc are made from brass.

Unless it's just that the Herald grille is easier to return to shape than the flatter, less rigid Sovereign ones?

My red RP37 is among the pics that weren't accepted by the inbox at your email, so I'm posting pics of its interior here in lower resolution due to the limits on the forum, haven't forgotten that I'm sending them though, my next move being to send several mail pieces each with below the limit on it.

I had a blue RP37A with the bigger ELAC speaker, but haven't seen many so I guess it was a very few of the last made that came with that whopping great thing shoehorned into there!

All of my 37As have, however, had the later fm tuner ie the one with the clear cover, I assumed that it was only the RP37 that had the aluminium bodied type, along with a grey basket on its Goodmans speaker, most RP37As having a cadmium plated basket from Celestion but with a magnet of the same size as the Goodmans one.

Nice job with the upholstery work! I had intended to reupholster my RP25 first, but have decide to start with the '37 as it's more prominently displayed and more saggy round the grille.
And I like the red ones better!

I'm going to put the foam in there without glue though, as I suspect that it would flatten out and go crumbly again with adhesive, experiments here have suggested that this was the original cause of the problem but the rear door of my MK2 RP10 Herald, remade from gyproc and repainted grey as original, then recovered with the foam trapped around the grille aperture (don't worry if you're looking at your RP10, that's an early one and didn't have a rear grille), has shown no signs of losing its bounce in the 2 years since it was done.

Incidentally, if anyone has a spare handle end cover for the Herald, I'd swap a chromed one for it, as one of those on my RP37 is a chrome plated one and should be finished to match the grille, handle (which curiously hasn't lost its red rexine strip on this set), hinge, and knob flanges. It bugs me but only when I see them both at once, so not often!

Paul_RK · 24th Sep 2006, 6:25 pm

Hi Simon,

Good to see this one, not least the foam renewal. Among a large assortment of the bigger Hackers here I have probably about three sets whose foam continues to do its intended job pretty well, and probably it's only a matter of time with those. The other sets get to look a little sorry for themselves no matter how good their conditon in other respects.

Quote:

Originally Posted by GJR 11L

All of my 37As have, however, had the later fm tuner ie the one with the clear cover, I assumed that it was only the RP37 that had the aluminium bodied type, along with a grey basket on its Goodmans speaker, most RP37As having a cadmium plated basket from Celestion but with a magnet of the same size as the Goodmans one.

Yes: to quote a (slightly ungrammatical) March 1971 Service Manager's News Letter from Hacker, "the difference between the RP25A 'Sovereign' and the RP25, and the RP37A 'Herald' compared with the RP37, are only concerned with a change of VHF tuner..." I somehow doubt the loudspeaker switchover was quite synchronised with the model number change, but can't currently get at my own RP37s to check for exceptions.

Regards,
Paul

24th Sep 2006, 2:16 pm	#1
Superhet Si Pentode Join Date: Jun 2006 Location: Crawley Down, West Sussex, UK. Posts: 151	An unloved Hacker Herald VHF restored Last week I won a Red Hacker Herald RP37A sold as non working with a suspect power switch. When the set arrived I could see straight away this radio was in need of some serious work. The grill was stoved in an badly corroded, the volume pot/switch was unserviceable, the trim on the handle looked like it had been stuck on with no nails and the rexine was very saggy on the front. It did however have a good aerial and a Elac speaker fitted, which I have never seen on these sets before. So I set about stripping the chassis out and removing the volume pot. Once I had the old pot out I fitted one from a donor Rp35. Time to see if the thing would power up. I wired an ammeter is series with the battery lead and powered the radio up out of chassis. All I was rewarded with was a loud switch on thump and no sound. At this point the current consumption was ~30mA, and although not very high, is to much for this radio in an idle condition. Looking around the Amp board soon found a shorted AC176 NPN output transistor. Great No spare transistors So the Rp35 again gave up it's working amp for the Rp37A. Upon switch on this time the radio showed some signs of life but did seem very insensitive. I thought at this point I would come back to this problem a bit later. Next the Front panel of the set was removed and the rexine peeled off the corners of the cabinet. The Front grill was removed and the dent pushed out better than I thought. Once all the rexine was lifted, I used a stiff brush to remove add the loose foam remaining between the cabinet and the rexine. I then cut up sections off high temperature pipe insulation to replace the space where the foam one belonged. Then it was a case of Evosticking the rexine down to the cabinet while stretching it to remove any creases. Once the rexine was dry the front of the set looked a million times better. I rebuilt the cabinet and replaced a few corroded battery stays along the way and was ready to sort out the lack of sensitivity. This later VHF set uses a different tuner board (type T309) and although it is mentioned in the service data, there is no alignment instructions. With a bit of working out, and the help of the circuit I soon found where the oscillator core was. Radio 2 was about 1 MHz off tune according to the scale calibration (which was checked before proceeding) so a tweak of the core bought it back where it was meant to be. Then the padder was tweaked to get Kiss FM to 100 MHz. A bit of time was taken to get the scale linearity correct but it soon was spot on. Still very insensitive Setting the set to 90Mhz I peaked the two cores for max output through the speaker. Then I went to 98Mhz and did the two remaining trimmers. Now I set was how it should be, sensitive and clear all the way through the range. Considering I was thinking of using this set for spares I am very pleased with the results. I have noticed a few things along the way though. 1 Brass grills are far weaker than the steel equivalents. 2 VHF Hackers oscillators always seem to drift with age. If you would like to see the results and the foam padding I used, follow the link below to the Hacker picture gallery. __________________ My Youtube channel https://www.youtube.com/user/simonspiers

24th Sep 2006, 4:38 pm	#2
howard Nonode Join Date: May 2005 Location: Godalming, Surrey, UK. Posts: 2,593	Re: An unloved Hacker Herald VHF restored Hello Simon, I was offered one of these recently and turned it down cos its brightwork was badly deteriorated (plus it was missing its aerial). I've seen these red Heralds come and go on that well known online fleamarket and none have looked in particularly good condition I daresay there are one or two nice examples around and I hope to find one cos these are really nice looking Hackers. I saw your restoration of this one on your website, I haven't 'responged' a Hacker cos I haven't found any suitable sponge to date so I have two or three to do when I eventually find some. Well done, nice to see one of these pretty radios working well and looking smart again Howard

24th Sep 2006, 5:59 pm	#3
GJR 11L Heptode Join Date: May 2004 Location: Ellington, Northumberland, UK. Posts: 815	Re: An unloved Hacker Herald VHF restored Hi Simon, I found this particularly interesting as I've never actually met a Herald or Sovereign with a steel grille, all of my RP18s/25s/30s/35s/37s/37As etc are made from brass. Unless it's just that the Herald grille is easier to return to shape than the flatter, less rigid Sovereign ones? My red RP37 is among the pics that weren't accepted by the inbox at your email, so I'm posting pics of its interior here in lower resolution due to the limits on the forum, haven't forgotten that I'm sending them though, my next move being to send several mail pieces each with below the limit on it. I had a blue RP37A with the bigger ELAC speaker, but haven't seen many so I guess it was a very few of the last made that came with that whopping great thing shoehorned into there! All of my 37As have, however, had the later fm tuner ie the one with the clear cover, I assumed that it was only the RP37 that had the aluminium bodied type, along with a grey basket on its Goodmans speaker, most RP37As having a cadmium plated basket from Celestion but with a magnet of the same size as the Goodmans one. Nice job with the upholstery work! I had intended to reupholster my RP25 first, but have decide to start with the '37 as it's more prominently displayed and more saggy round the grille. And I like the red ones better! I'm going to put the foam in there without glue though, as I suspect that it would flatten out and go crumbly again with adhesive, experiments here have suggested that this was the original cause of the problem but the rear door of my MK2 RP10 Herald, remade from gyproc and repainted grey as original, then recovered with the foam trapped around the grille aperture (don't worry if you're looking at your RP10, that's an early one and didn't have a rear grille), has shown no signs of losing its bounce in the 2 years since it was done. Incidentally, if anyone has a spare handle end cover for the Herald, I'd swap a chromed one for it, as one of those on my RP37 is a chrome plated one and should be finished to match the grille, handle (which curiously hasn't lost its red rexine strip on this set), hinge, and knob flanges. It bugs me but only when I see them both at once, so not often! Attached Thumbnails __________________ John. Last edited by GJR 11L; 24th Sep 2006 at 6:07 pm.