Hmv 1128

[Beardyman]

This set came to me looking rather the worse for wear, the paint on the front panel was falling off & it didn't need a lot of encouragement to divest itself of said coating.
The case was very dull but this was mainly ground in dirt, the HMV logo had not faired well, its mostly gone.
I have yet to find a good quality replacement for these or one that doesn't cost the earth & come from half way round the world!
The front panel had experienced some kind of heat damage, possibly from being in a sunny window but I'm guessing here.
I took it to a neighbour who restores vintage vehicles, his opinion was that no amount of prep would give a smooth surface.
He then said, "You know the old saying? If you can't hide it then make a feature of it! Try a textured paint, there's plenty around".
I followed his advice and found a water based textured paint, it needed 24 hours to dry but the end result was, I think, very acceptable.
The case polished up well, surprisingly so in fact.
Sometimes the dirt & grime seems to the surface.
Getting the chassis out was a mission!
I followed the manufacturers instructions to the letter but it would not slide out.
I found the problem eventually, there are two pillars protruding from the front face of the case which locate into holes in the chassis, these were binding/digging in every time I tried to extract it.
By pulling one side out slightly before the other it came out but still with some difficulty, I smeared a very thin film of silicone grease onto the pillars which was just enough to prevent the chassis picking up on them. Once the chassis was out it was time for a good dusting, there was plenty of it too!
Whilst cleaning the back plate to the tuning scale a veritable avalanche fell off, this set the cat off sneezing (she likes to watch what I'm doing) which exacerbated things, great clouds of fine dust rose!
I gave up as I was now sneezing as well & took the chassis outside.
I find makeup brushes are great for this as they can get into all the nooks & crannies without causing damage.
All in all it wasn't in bad condition, no obvious signs of damp which is always a good thing.
The tuning cord was in good order but the VHF tuning mechanism was seized solid, as this is a variable inductor arrangement great care was needed.
After completely disassembling the cam/lever mechanism & cleaning every rotating/rubbing surface it now works quietly & smoothly, fortunately the cores weren't jammed, that may have been a show-stopper.
All valves out & filament checked, all apparently good.
Stowed away in bubble wrap in a shoebox I carried on with checking the transformers, again, all good.
Onto the passives now, about 75% of the resistors had gone high, some by as much as 75% but none below 30%.
All the wax paper capacitors were way off their printed values, this set has a fair few ceramic types which were all spot on.
Both scale bulbs blown, a quick root around the spares boxes found replacements.
The smoothing capacitor (32-32-16uf) didn't show any external signs of distress & re-formed very well, less than 0.5mA leakage from any section.
A quick check of the mains switch showed it was not switching, these pots are fairly simple to take apart but more importantly, fairly easy to put back together!
Inside the switch the grease had dried out stopping it from moving, cleaned & re-greased it worked well.

I like to power the chassis up initially without valves just to check the voltages are where they should be & the mains transformer (if it has one) doesn't get stressed.
With a new mains lead fitted & a good earth made power was applied via the variac.
Nothing, not a sausage, not even the scale bulbs were lit!
Mains up to the twin 1A fuses ok, nothing after the fuses, eh?
Power off, check the fuses for continutiy, no problem there, all good.
The inside surfaces of the fuseclips were covered with a silvery white film, a devil to get off but a fibreglass pen sorted that out.
With the mains back on all was now well, voltages good, bulbs glowing & after 20 minutes or so the transformer was still cold.
Ok valves in, up gently on the variac, all glowing nicely.
Nothing on VHF, LW very quiet but MW worked.
I say worked, very distorted but working.
The distortion was the speaker, the voice coil was rubbing.
After loosening off the two securing screws, cutting out the dust cap & putting three acetate strips between the coil & pole piece I managed to re-align it enough to not rub.
MW was now clear & picked up the usual stations around here.
LW was a different matter, this was down to poor joints (old ones) & bad contacts on the wafer switch, a quick squirt of Servisol & re-making said joints had it picking up Radio 4 quite well.
VHF was stone dead, after checking the cathode volts of the first half of the ECC85 against the manufacturers datasheet it was looking rather dead.
The datasheet said it should be around 1.4V, I was getting about 500mV.
No volts dropped across the anode resistor either so no current being conducted.
After replacing the ECC85 VHF was working but sounding very thin.
I hooked it up to the bench speaker, sounded good, plenty of bass, good treble.
Then it finally dawned on me the speaker needed to be in the case, obvious really!
Re-assembled, it now looks & sounds really rather good.

[vinrads]

I enjoyed the write up with a cuppa this morning , well done with the restoration ,I quite like the stone chip effect paint ,nice to see that the dial has survived unscathed , Mick.

[Beardyman]

Thank you for your kind words, much appreciated.
I was surprised the scale was in such good condition considering the rest of the set was, shall we say, rather grim?
Glad you enjoyed the write up.