I've been working on this during the forum's absence.
According to both the Trader and Bush data that shunt resistor should be 30Ω so I fitted a 33Ω. The dial lights still seemed a bit temperamental but seemed to be OK until they both did a flash-gun impression. I then discovered that they should only be 3.5V and I'd fitted 6.5V ones so something was definitely up still.
Another mystery was that the HT seemed sky-high. I traced this to R34 (Bush number) which should be 160Ω having been replaced with a 33Ω. It looks like somebody had mixed the value up with the number.
I fitted a 200Ω but it still seemed high. I then decided that if the meter was telling me things I didn't want to hear use another one. The problem was my not having realised that the numbers on the sheet were for an AVO7 and with my old 2000V/Ω thing they were close enough for rock and roll.
Apart from that it was a re-cap, which I did one at a time hoping that the voltages would start to make sense, and a partial re-wire.
I kept checking the lamp voltage and, as it kept spiking, I added an extra grounding wire to the resistor and it seemed fine thereafter.
The only 3.5V lamps I've got are 300mA and too dim (they should be 150mA) so I'll be fitting LEDs. I've had to order some as I popped one while testing. At least I've got plenty of MES bases!
The radio is playing as I type this and sounds great. In fact it may replace the DAC90a as my favourite.
- Joe
According to both the Trader and Bush data that shunt resistor should be 30Ω so I fitted a 33Ω. The dial lights still seemed a bit temperamental but seemed to be OK until they both did a flash-gun impression. I then discovered that they should only be 3.5V and I'd fitted 6.5V ones so something was definitely up still.
Another mystery was that the HT seemed sky-high. I traced this to R34 (Bush number) which should be 160Ω having been replaced with a 33Ω. It looks like somebody had mixed the value up with the number.
I fitted a 200Ω but it still seemed high. I then decided that if the meter was telling me things I didn't want to hear use another one. The problem was my not having realised that the numbers on the sheet were for an AVO7 and with my old 2000V/Ω thing they were close enough for rock and roll.
Apart from that it was a re-cap, which I did one at a time hoping that the voltages would start to make sense, and a partial re-wire.
I kept checking the lamp voltage and, as it kept spiking, I added an extra grounding wire to the resistor and it seemed fine thereafter.
The only 3.5V lamps I've got are 300mA and too dim (they should be 150mA) so I'll be fitting LEDs. I've had to order some as I popped one while testing. At least I've got plenty of MES bases!
The radio is playing as I type this and sounds great. In fact it may replace the DAC90a as my favourite.
- Joe
