Build another Bush DAC90 from salvaged parts.

[Murphyv310]

Good work David.
Much more pleasant than "Tuning in" JVC Smart TVs.

[Geordie McBoyne]

Hi Trevor,
At least I got results from my work on the valveholder adaptors. Something to show for my travails but certainly not so lucky with that "JVC" not so smart TV. Who wants a TV that shouts "service" at you when something of no significance happens during the course of the program?

Geordie McBoyne.

[bobhowe]

Five adaptor plates made in a day.  It took two and half hours to make these.  Of course I could have saved time by just fitting the plates in their original form. Second attachment.
Now I must find five B8A valveholders, or four B8A and one B9A if I decide to use an UCH81 as the frequency changer.

Geordie McBoyne.

Hi David got 4 B8A valve holders & an UCH 81 valve spare as well you will have better luck wit the DAC90 than the not so smart TV kind regards Bob

[Geordie McBoyne]

Hi Bob,
many thanks again. Reckon I could have this set fully assembled by the weekend. Some component values will have to be changed as a result of using U40 series valves instead of the older 0.2amp octal types. Will compare the DAC90 and DAC90A service manuals.

Geordie McBoyne.

[bobhowe]

Hi David no problem see you tomorrow kin regards Bob

[bobhowe]

Hi David no problem see you tomorrow kin regards Bob

Hi been to Davids shop to day to drop of some DAC90 parts and  the adapter plates look great  done a good job cutting the chassis for the DAC90 speaker magnet clear the chassis . The build continues 

[Geordie McBoyne]

The attachment shows the partially assembled chassis. Note the adaptor plates to fit B8A valveholders in lieu of the octal sockets.
Both IF transformers have that common fault of detached iron dust tuning cores.  It's usually the lower core that seems to go first. Superglue is ideal to effect a repair.
The core attachment bars are riveted to the paxolin end pieces. In the transformers I recently repaired in another DAC90 the metal bars were fixed into position with screws.

Geordie McBoyne.

[bobhowe]

Hi David looking good it will not be long before we hear the first squeak from it kind regards Bob

[Geordie McBoyne]

The long and medium waveband oscillator coils were taken from a scrap DAC90 chassis.  A type of coil I've never seen before in a DAC90 in as much these have adjustable iron dust cores.  This makes it necessary to relocate the coils on the chassis to permit easy access for adjustments. Having those adjustable cores means more accurate alignment of the low frequency end of the waveband will be possible.

Geordie McBoyne.

[Geordie McBoyne]

More progress. The IF amplifier, detector and audio amplifier completed and have reached the grid and cathode of the UL41 output valve.

Geordie McBoyne.