Bush dac10 - UK Vintage Radio Repair and Restoration Discussion Forum

mark pirate · 4th Aug 2008, 8:26 pm

Forgot i had this one

so as i had time i tackled this set today.
I like these sets even more than dac 90a's (to look at anyway)
They do have their problems though, the dial surround tends to crack around
the fixing screws & they also can have problems with the 'back to front' speaker that is unique to this set. Happily, this set had no such problems.
after removing the chassis i found two dates, feb 1950 & mar 1950.
So that makes it an early set. Apart from some disintigrating rubber wiring & a
lot of dust, it looked ok, so after some checks with a meter i powered it up via my variac, it soon crackled in to life

& sounded good with plenty of volume, after a bit of switchcleaner & replacing dial lamp & speaker wiring
i checked the caps & only had to replace the mains filter & decoupler.
It was owned by a 60 a day smoker by the state of the innards

so after a good clean i set about the cabinet using my usual methods
(t-cut & silicone polish) as can be seen below it came up a treat
(after 3 hours!!) i then set about re-assembly.
On powering up again, all was fine, then disaster

blue sparks flying round the uy41 rectifier, luckily i had a good replacement, the set then came on fine
so on with the back, then soak test, it has been running for 3 hours hours so far with no problems

Cheers
Mark

MALC SCOTT · 4th Aug 2008, 9:01 pm

Hi Mark, a very nice job you have done. I like these sets and own a couple of them. I was told they were made for blind people?? It might be a good thing to replace all of the wax caps. I am sure they must be all about knackerd.
Cheers, Malc.

mark pirate · 4th Aug 2008, 9:21 pm

Hi malc, i only replace out of spec caps, on this set there were only two duff
ones

Yes, these sets were supplied by wireless for the blind, i saw a rough
example at a car boot sale with the wireless for the blind sticker on it. (didn't
buy it though) maybe they liked the 3 preset stations?

Mark

Sideband · 4th Aug 2008, 9:48 pm

How did you check the caps? I would strongly suggest you at least change the audio coupling cap...even a small leak will cause problems. It could also cause long-term problems with the output transformer if the output valve should start drawing too much current. Then again, it's your radio.....

Rich.

mark pirate · 6th Aug 2008, 8:14 am

Hi Richard, Don't worry, the first cap i always change is THAT cap

ul41's are getting expensive!! The reason it didn't need many caps replaced was that the set was used regularly since new, but the previous owner told me that he switched on one day & it went bang & started smoking

This was due to the mains filter cap expiring, so this was replaced with an X2
rated cap (after cleaning the waxy mess away from the innards)
I was sold the set for parts only, as the previous owner was told 'it is beyond repair, you cant get the parts anymore & sets of this age are dangerous'
Makes me wonder where he tryed to get it repaired

Cheers
Mark

Sideband · 6th Aug 2008, 8:34 pm

Quote:

Originally Posted by mark pirate

I was sold the set for parts only, as the previous owner was told 'it is beyond repair, you cant get the parts anymore & sets of this age are dangerous'
Makes me wonder where he tryed to get it repaired

Cheers
Mark

In that case I have a house full of dangerous equipment ready to catch fire or electrocute me at any moment.....

howard · 6th Aug 2008, 8:55 pm

Well Done Mark

It looks mint now, well done.

I have one of these too, but I replaced all the wax capacitors even though it meant removing the tuner unit, a fiddly job. I seem to remember that all the old caps in mine were leaky ...

Howard

mark pirate · 6th Aug 2008, 9:53 pm

Quote:

In that case I have a house full of dangerous equipment ready to catch fire or electrocute me at any moment.....

Well i think that means all of us

Mark

mark pirate · 7th Aug 2008, 10:56 am

Hi all, just remembered that 4 of the valves (mullard) had metal base rings
i can't every recall seeing any of these before, maybe early versions?

Mark

Sideband · 7th Aug 2008, 1:36 pm

They are early versions of the B8A base. Later ones did away with the metal base.

Rich.

mark pirate · 7th Aug 2008, 6:42 pm

Thanks for the info, Richard. As i said this is an early set & these must have been the original valves, shame the uy85 died on me

Mark

4th Aug 2008, 8:26 pm	#1
mark pirate Dekatron Join Date: Mar 2008 Location: Worthing, West Sussex, UK Posts: 5,185	Bush dac10 Forgot i had this one so as i had time i tackled this set today. I like these sets even more than dac 90a's (to look at anyway) They do have their problems though, the dial surround tends to crack around the fixing screws & they also can have problems with the 'back to front' speaker that is unique to this set. Happily, this set had no such problems. after removing the chassis i found two dates, feb 1950 & mar 1950. So that makes it an early set. Apart from some disintigrating rubber wiring & a lot of dust, it looked ok, so after some checks with a meter i powered it up via my variac, it soon crackled in to life & sounded good with plenty of volume, after a bit of switchcleaner & replacing dial lamp & speaker wiring i checked the caps & only had to replace the mains filter & decoupler. It was owned by a 60 a day smoker by the state of the innards so after a good clean i set about the cabinet using my usual methods (t-cut & silicone polish) as can be seen below it came up a treat (after 3 hours!!) i then set about re-assembly. On powering up again, all was fine, then disaster blue sparks flying round the uy41 rectifier, luckily i had a good replacement, the set then came on fine so on with the back, then soak test, it has been running for 3 hours hours so far with no problems Cheers Mark Attached Thumbnails

4th Aug 2008, 9:01 pm	#2
MALC SCOTT Octode Join Date: Aug 2006 Location: Willington, County Durham, UK. Posts: 1,499	Re: Bush dac10 Hi Mark, a very nice job you have done. I like these sets and own a couple of them. I was told they were made for blind people?? It might be a good thing to replace all of the wax caps. I am sure they must be all about knackerd. Cheers, Malc. __________________ Malc Scott

4th Aug 2008, 9:21 pm	#3
mark pirate Dekatron Join Date: Mar 2008 Location: Worthing, West Sussex, UK Posts: 5,185	Re: Bush dac10 Hi malc, i only replace out of spec caps, on this set there were only two duff ones Yes, these sets were supplied by wireless for the blind, i saw a rough example at a car boot sale with the wireless for the blind sticker on it. (didn't buy it though) maybe they liked the 3 preset stations? Mark

4th Aug 2008, 9:48 pm	#4
Sideband Dekatron Join Date: Oct 2003 Location: Croydon, Surrey, UK. Posts: 7,577	Re: Bush dac10 How did you check the caps? I would strongly suggest you at least change the audio coupling cap...even a small leak will cause problems. It could also cause long-term problems with the output transformer if the output valve should start drawing too much current. Then again, it's your radio..... Rich. __________________ There are lots of brilliant keyboard players and then there is Rick Wakeman.....

6th Aug 2008, 8:14 am	#5
mark pirate Dekatron Join Date: Mar 2008 Location: Worthing, West Sussex, UK Posts: 5,185	Re: Bush dac10 Hi Richard, Don't worry, the first cap i always change is THAT cap ul41's are getting expensive!! The reason it didn't need many caps replaced was that the set was used regularly since new, but the previous owner told me that he switched on one day & it went bang & started smoking This was due to the mains filter cap expiring, so this was replaced with an X2 rated cap (after cleaning the waxy mess away from the innards) I was sold the set for parts only, as the previous owner was told 'it is beyond repair, you cant get the parts anymore & sets of this age are dangerous' Makes me wonder where he tryed to get it repaired Cheers Mark

6th Aug 2008, 8:55 pm	#7
howard Nonode Join Date: May 2005 Location: Godalming, Surrey, UK. Posts: 2,593	Re: Bush dac10 Well Done Mark It looks mint now, well done. I have one of these too, but I replaced all the wax capacitors even though it meant removing the tuner unit, a fiddly job. I seem to remember that all the old caps in mine were leaky ... Howard

7th Aug 2008, 10:56 am	#9
mark pirate Dekatron Join Date: Mar 2008 Location: Worthing, West Sussex, UK Posts: 5,185	Re: Bush dac10 Hi all, just remembered that 4 of the valves (mullard) had metal base rings i can't every recall seeing any of these before, maybe early versions? Mark Attached Thumbnails

7th Aug 2008, 1:36 pm	#10
Sideband Dekatron Join Date: Oct 2003 Location: Croydon, Surrey, UK. Posts: 7,577	Re: Bush dac10 They are early versions of the B8A base. Later ones did away with the metal base. Rich. __________________ There are lots of brilliant keyboard players and then there is Rick Wakeman.....

7th Aug 2008, 6:42 pm	#11
mark pirate Dekatron Join Date: Mar 2008 Location: Worthing, West Sussex, UK Posts: 5,185	Re: Bush dac10 Thanks for the info, Richard. As i said this is an early set & these must have been the original valves, shame the uy85 died on me Mark