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Old 31st Jul 2016, 5:04 pm   #1
Al (astral highway)
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Smile Hacker Serenade RG16

I have just completed a restoration of this neat little radiogram, date of manufacture, 1965. It belongs to the father of a friend of mine, who has owned it since it was manufactured more than 50 years ago. It apparently cost the equivalent of two week's or more average wages at the time, and the owner is, unsurprisingly, sentimentally attached to it. So it means a lot to me to be able to return the set working, knowing it will put a big old smile on the owner's face.

Hacker did something quite interesting here: the footprint of the set is only a about one and a half times wider than the Garrard AT6 deck. This makes it much more appealing (to me, at least) than the huge, oversized radiograms that we sometimes see gathering dust. Hacker made a truly classy evolution here - it must have been striking at the time.

The set is sophisticated and has a relatively high component count. It has a very high quality, Stereo, tuner, and was designed to playback in stereo by plugging into another amplifier speaker made by Hacker. The ten valves, three chassis, three speakers and high component count add up to quite a weight: not quite a boat-anchor, but just under 20Kg!!

The PA on-board is a well designed push-pull affair with two output valves. Unusually, these operate in a horizontal position. The main speaker is flanked by two tweeters for better frequency response.

The set was unresponsive on power-up, but I could see no evidence of any catastrophic failure and all the valve heaters were intact on a brief initial inspection. I removed the output valves and reformed the main power supply electrolytics for 24 hours.

The deck, surround and tuner indicator panel were coated in grease and thick dust - so thick that I couldn't see - let alone locate - the cabinet screws securing the deck. The tone arm and surrounding mechanism were also stained dark yellow.

First up I vacuumed away dust from the top of the set and removed
the three monoblocks making up the set - the PA and power supply on one chassis, the tuner on another, and the tone control circuit on a small PCB.

This gave me access to the dust in the cabinet, as well as to flammable and unsightly piles of completely degraded foam from the speaker baffle. This was just everywhere and I vacuumed and air-dusted it out as a first step.

I removed the deck and carefully cleaned the tone arm, as well as all the surrounding plastic, first with warm water and detergent and then with methylated spirits and cotton buds. This took a good while over several sessions. Next up, I removed the panel containing the glass tuning indicator and carefully cleaned both sides.

Given the age of the set, I replaced all electrolytics on sight, as well as all grid-coupling caps - the usual 0.047uf candidates.

Initially I thought that the large yellow ('Supamold) caps shown in the discarded component tray (see pic) were poly replacements of previous grid-coupling caps, but this very useful thread showed otherwise. They were all leaky. These and all other Hunts caps were also replaced.

These very routine fixes were all that was needed electronically. I initially thought the Magic Eye tuning indicator wasn't working, but it was first of all an issue with the AM bypass cap, which I replaced - very helpful advice here from forum members, again in a separate thread.

It also needed the sensitivity control to be more engaged, and also responded to a makeshift dipole instead of a long wire.

On the tone control board, I found a loose PCB track. Handily, the opposite side contained an insertion point for a wire leading to the volume control. I stripped this out and replaced it with a heavy, stiff copper wire which I was able to pass through to the other side. Because of the tension I was able to produce using this thicker-than-original wire, the track was nicely pulled back under a high degree of mechanical tension. I epoxied over the completed solder joint to add further stability.

I also found a blown MOX resistor, degraded through age, which I replaced. The (Baxandall) tone control circuit needed some care, too. All associated passive components on the bass side were suspect. The log pot was also partially open circuit. Thanks also to forum members who contributed to the relevant thread!

The last electronic intervention was to replace the non-polarised 1uf cap for the tweeters.

Next up, I used Aquanol to clean all valve pins and sockets, and also to all other bespoke plugs and sockets (the set uses numerous of these for ease of maintenance).

These trivial fixes were enough to get the tuner and PA going perfectly again.

As there was originally no interference suppression, I added 0.1uf Y2 caps, one phase to earth and one neutral to earth. The leads are heatshrink wrapped and strain-relieved.

Finally, I gave some attention to the front of the cabinet. Here, 48 veneer strips had deliminated and I carefully glued them back again. First I sized the backing with PVA, then once that layer had been absorbed, I applied another coat, really fiddly work with a small paintbrush. I figured that if I could slow down the rate of evaporation from the adhesive, it would penetrate better into the substrate. So I taped over the whole of the front baffle with parcel tape while the glue was hardening.
My theory worked out fine - two days later, I removed the tape and found all of the strips and surrounding veneers well-bonded.

I completed the restoration by applying a few dabs of teak wood dye where necessary, then by wiping the cabinet with Danish Oil.

It's a wonderful little set and I hope others with one in the workshop might be inspired to get theirs going. There's a pretty amazing quality of sound reproduction, well worth listening to.

Thank you to all the forum members who contributed to all associated threads. It was fun and instructive to share my journey with you, and the result is very pleasing.
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Old 31st Jul 2016, 6:27 pm   #2
Nickthedentist
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Default Re: Hacker Serenade RG16

Nice to hear of your outcome, Al, and that someone else has bothered bringing one of these nice units back to life.

I have two, both from eBay for about £30 a piece. One is now in daily use and gives me a great deal of pleasure. I was lucky enough to be given a matching AL16 stereo extension LS/Amp by ValvoStef which is nearing the top of the to-do pile.

The AT6 IIa decks on mine were pretty much seized so had to be stripped down to the very last washer, but the time spent was well worthwhile. Furthermore, the 9TAHC cartridges were well past their best, an SC12M being an ideal replacement.

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Old 31st Jul 2016, 6:36 pm   #3
Al (astral highway)
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Default Re: Hacker Serenade RG16

Quote:
Originally Posted by Nickthedentist View Post
Nice to hear of your outcome, Al, and that someone else has bothered bringing one of these nice units back to life...

The AT6 IIa decks on mine were pretty much seized so had to be stripped down to the very last washer, but the time spent was well worthwhile. Furthermore, the 9TAHC cartridges were well past their best, an SC12M being an ideal replacement.
Thanks, Nick; I'm pleased to hear that you're enjoying yours and it will be great to hear what the whole rig sounds like once you've restored the extension speaker/ amp! Also thanks for the tip about a good substitute cartridge!
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Old 1st Aug 2016, 5:59 pm   #4
Nuvistor
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Default Re: Hacker Serenade RG16

It looks very good, always liked Hacker products.
Frank
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Old 1st Aug 2016, 8:19 pm   #5
Al (astral highway)
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Wink Re: Hacker Serenade RG16

Quote:
Originally Posted by Nuvistor View Post
It looks very good, always liked Hacker products...Frank
Thanks, Frank! I handed it back to the owner's son today. He was completely wowed by the sound. He had only previously heard it in failing condition (with the grid coupling caps going progressively leakier over time) and just couldn't believe the quality of what he was hearing.

I can't wait to hear what his old father says when he gets it back. It will have been a very, very long time since he saw or heard it in that condition!
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