There have been a couple of diversions to this Thread while I sorted out issues with the
Bush DAC10 - MW Frame Aerial and
Restuffing Dual Electrolytic Can Capacitor. These are now resolved, hopefully, and we can get back on track with this set?
I did experience another slight delay as I'd forgotten about the wiring and soldering associated with the Output Transformer and Loudspeaker which all had to be replaced - some more solder joints for you to peruse: -
The Tone correction capacitor (C24) that was fitted across the Primary of the Output Transformer was 0.022uF whereas the Bush Service Instructions lists this as 0.1uF, so this was changed accordingly. The replacement was a 1kV capacitor, just in case!
So for the first time we were able to re-assemble all the component parts of this set preparing for an initial live switch on, with the lamp limiter of course! Flick the switch and watch the bulb in the lamp limiter initially dim and then slowly brighten as the radio came alive!
First thing I noticed was no hum which I can only put down to the new reservoir and smoothing caps, proving that my re-stuffing exercise had been successful? Reception on MW was surprisingly good which amazed me as this was using my new Frame Aerial winding although LW was quite poor with only a couple of stations with lots of background noise! The on-off switch/volume control did not have any scratchiness which was more good news. Switched from Lamp to Direct after about half an hour and everything sounded a bit better but still not great on LW.
Still work to be done...
Time to take some voltage readings for the various valve pins - input mains voltage was 240V AC at the time with the receiver set to MW range with no signal. Values stated are as specified in the Bush Service Instructions while those in brackets are what was measured: -
V1 UCH42
Pin 2 98 (76.8)
Pin 3 47 (39.9)
Pin 5 47 (40.2)
Pin 7 N/A (0.84)
V2 UF41
Pin 2 74 (58)
Pin 5 57 (46)
Pins 3,4 & 7 0.8 (0.96)
V3 UBC41
Pin 2 74 (45.2)
Pin 7 1.3 (0.96)
V4 UL41
Pin 2 190 (178)
Pin 5 98 (77.1)
Pins 3 & 7 5 (3.9)
V5 UY41
Pin 2 220 A.C. (194 A.C.)
Pin 7 205 (189)
The HT seems low all across this set but I'm sure there is a lot more going on - any advice or guidance would be welcomed??
I'm going to check again and remind myself which LW and MW stations should be available for my local transmitter and see how these correlate with the stated wave ranges.
I know that FM and Freeview come from Black Hill but wasn't aware that MW and LW transmissions came from Westerglen and Dechmont Hill - see this page: -
Radio stations in Glasgow
As I've installed a new MW winding on the Frame Aerial I've assumed that some from of re-alignment will need to be carried out with this set. With the tuning capacitor vanes fully meshed the Cursor isn't too far off the datum line on the auxiliary calibration scale: -
