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sobell1980 · 21st Feb 2021, 11:58 am

Good morning. Spent some time on the set yesterday. Turns out the EZ80 was causing the low HT issue alongside some resistors that had gone high. Not massively but about 10% out of spec so I decided to change them.
I refitted the old EZ80 to confirm my original low readings. The HT took forever to get up to 160v and slowly struggled to climb up to about 200v and stopped there. Putting the new EZ80 in I watched the HT rocket to 260 v at the EZ80 cathode.
Here are now my current readings.

V2 (a) anode 93v
(b) anode 126v
Screen 115v
Cathode 1.73v

V3 anode 180v
Screen 115v
Cathode 1.75v

V4 anode 174v
Screen 160v
Cathode 1.75

V5 anode (d) 79v
No other readings available for V5

V6 anode 242v
Screen 220v
Cathode 6.85v

V7 both anodes 240v ac
Cathode 260v dc

Tuning indicator anodes 170v and 25v anode fed after resistor.

I have two queries on these readings.

V6 anode is still slightly low at 242v compared to the quoted 245v and using a DMM should read higher anyway. ?

Valve 4 cathode is 1.75v compared to the quoted 2.3v ?

The set peforms loud on FM and very selective.
MW is 'okay' on full volume and LW is still poor. I've tried the set in the kitchen to see if it's a signal issue and with a long length of coax to see if MW and LW will improve but it didn't make a vast amount of difference. I tried my transistor set in the radio room I work in and it picks up MW and LW loud and clear with its internal aerial.
Perhaps I now need to try the alignment of AM circuit's and if no further improvement can be made perhaps this is as good as the set is, which in my eyes is disappointing for such a nice looking set.

21st Feb 2021, 11:58 am	#17
sobell1980 Octode Join Date: May 2011 Location: Bromyard, Herefordshire, UK. Posts: 1,241	Re: Bush VHF61 repair. Good morning. Spent some time on the set yesterday. Turns out the EZ80 was causing the low HT issue alongside some resistors that had gone high. Not massively but about 10% out of spec so I decided to change them. I refitted the old EZ80 to confirm my original low readings. The HT took forever to get up to 160v and slowly struggled to climb up to about 200v and stopped there. Putting the new EZ80 in I watched the HT rocket to 260 v at the EZ80 cathode. Here are now my current readings. V2 (a) anode 93v (b) anode 126v Screen 115v Cathode 1.73v V3 anode 180v Screen 115v Cathode 1.75v V4 anode 174v Screen 160v Cathode 1.75 V5 anode (d) 79v No other readings available for V5 V6 anode 242v Screen 220v Cathode 6.85v V7 both anodes 240v ac Cathode 260v dc Tuning indicator anodes 170v and 25v anode fed after resistor. I have two queries on these readings. V6 anode is still slightly low at 242v compared to the quoted 245v and using a DMM should read higher anyway. ? Valve 4 cathode is 1.75v compared to the quoted 2.3v ? The set peforms loud on FM and very selective. MW is 'okay' on full volume and LW is still poor. I've tried the set in the kitchen to see if it's a signal issue and with a long length of coax to see if MW and LW will improve but it didn't make a vast amount of difference. I tried my transistor set in the radio room I work in and it picks up MW and LW loud and clear with its internal aerial. Perhaps I now need to try the alignment of AM circuit's and if no further improvement can be made perhaps this is as good as the set is, which in my eyes is disappointing for such a nice looking set.