Bush VHF61 Restoration

[Murphyv310]

Hi.
I was recently asked to restore a VHF61 that has been in the family since it was new.
On first glance the cabinet was extremely dull, the gold metal strip wasn't brilliant and there was a crack on the bottom of the cabinet.
Later in the day I removed the back and had a look inside, the chassis was really dusty, possibly the thickest I've seen for many years, fortunately a non smoker house
I then removed the chassis and gave the whole set a good vacuum and after stripping the cabinet gave that a wash in good old TFR.
At this point I decided to power up the set on the variac. After I got to around 150v there was no signs of clicks or any response from the speaker, A check on the HT revealed around 100v but nothing on the EL84 Anode. I then traced out the problem as the primary winding of the output transformer to be O/C. Not having a Bush transformer I substituted an EL84 output transformer from an old Pye radiogram.
After fitting the transformer I powered up the set again and was rewarded with good results on medium and long wave, VHF was quite deaf.
I felt the audio was quite bassy.
Next was to check and replace all suspect capacitors, the Audio coupling caps were the first to be done along with the .005uf cap on the tone control. I replaced all the decouplers in the ECH81 and two EF89 stages with the exception of 4 that I normally leave, these are the heater decouplers and cathode bypass caps on the EF89's, I do though bridge them and any improvement I'll just change them.
Performance then improved greatly after the work and after substituting an ECC88 in place of the ECC85 made a huge difference on VHF.
The next issue was the amount of Bass in the audio, the speaker was really rattling at anything above low volume. I put this down to the different transformer so a small change to the NFB and adding a 330uf coupling cap to the speaker has made the Audio just right. I also replaced the EL84 as it was slow warming and low emission.
Next was a new mains cable with a 1 amp fuse in the plug, I did a full PAT on the set and it passed the flash test perfectly.
I then used Gorilla super glue on the crack on the bottom of the cabinet and araldited a square plastic piece 5mm thick to the inside of the cabinet for reinforcement.
Next was to buff up the case, I use a car headlamp refurbishing rotary pad for this and it makes a big difference to the cabinet and finish, I also sorted out the gold trim and paintwork.
The set so far has been running for 13 hours continuously, I normally run them for 24 hours on soak test.
I'll give the customer a 12 month warranty.

[radioman]

Excellent work Trevor - that chassis looks like new !
I think I've got nearly as many Bush sets in my collection than I do of Murphys but I've not got a VHF61.
I'm sure your customer will be very happy.

Regards,
Andy

[Murphyv310]

Thanks Andy.
The set has had a 13 hour test and has been running on Radio 2 since 8:30. No problems and no drift. I think I'll be able to deliver the set after tomorrow.
Nice enough set to work on with only one capacitor a little fiddly to do. Resistors were mostly well within spec and the smoothing capacitor up to value with a good ESR reading for an original component.

[boater sam]

Smart Trevor, they do clean up well. Did the EM80 work too?
Had a count up last night, there seems to be six  VHF61s in the workshop! I'm sure there were less last year, are they breeding?

[Geordie McBoyne]

Hi Trevor,
             Excellent sets, as good as any of the Continental rivals.  The attachment shows the rear chassis of a VHF64. It's evident the two sets don't share the same chassis metalwork design. VHF64 chassis is 445mm wide.  I understand the pre-detector stages are similar to the VHF61 along with the two EF89 IF stages but the output stage is different having been designed to drive two large loudspeakers and the Grundig sourced tweeter.

The VHF64 works but the cabinet needs seeing to. Where does one source material for those gold bands which should be present at the ends of the cabinet?  I'm planning to give the set a dark piano finish.

Geordie McBoyne.

[boater sam]

Car coach lining tape, Geordie.

[Murphyv310]

Smart Trevor, they do clean up well. Did the EM80 work too?
Had a count up last night, there seems to be six  VHF61s in the workshop! I'm sure there were less last year, are they breeding?

Hi Sam.
Yes the EM81 was fine.
Last year was quite dead for vintage work but I had three amps to fix with a stereo 3-3 ordered too, sadly the customer did a bunk and has gone without a trace.
This year so far I've had 3 vintage repairs...... very odd.

[Crackle]

Nice repair, that is how it should be done, systematically and professionally, and all in one post with clear photos.
It looks like the set was a joy to work on with easy access to most components. I really prefer to work on these types of sets to ones with printed circuits.

Mike

[Geordie McBoyne]

Car coach lining tape, Geordie.

Hi Sam,
           thanks for the tip.  The gold lines were a feature of all the 1956 range of Bush radio and TV products.
The dull but worthy looking Bush TV53 TV set was transformed into the more stylish TV63 simply by applying a darker lacquer finish and those gold lines.

Geordie McBoyne.