Bush TV22 MK 11 Restoration Update - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

Steve_P · 6th Sep 2007, 9:28 pm

I hope we're all working off the same diagram! For me, Trader Sheet 1091. If it's a different one, let me know! The part numbers are different....

C52 on my diagram is the one that feeds the volume control.

Anyway, first, tune for a perfect picture. Then check C10 and try a tweak of L6. This is adjacent channel sound rejection. The sound IF is taken off by L12/R13. Also check L25 and L27.

Hope this helps!

Cheers,

Steve P

taipai_royal · 7th Sep 2007, 7:33 am

Thanks Steve, C10 does not measure up to its spec,being low value is it safe to temporary
remove, no improvement with adjusting L6, I will try tweaking L25/27?.
Graham.

Ian - G4JQT · 7th Sep 2007, 9:30 am

Have you tried injecting some audio into the grid of the audio valve to see if the AF ccts are working properly?

If you have the equipment (or can borrow) 19.5 MHz with some mod straight into pin 2 of V3 (Bush service sheet numbering) bottom chassis to see if the sound IF is working.

I shouldn't tweak anything just yet unless it's obvious someone has been there before!

Ian

Steve_P · 7th Sep 2007, 10:00 am

Change C10, Don't try to line a circuit up with parts missing!!

Cheers,

Steve P

taipai_royal · 10th Sep 2007, 9:09 pm

Further progress has been hampered by a blown EF80, whilst waiting for a replacment I took a chance to check out the chassis wiring and recap routing. Looking under the reciever unit I noticed a missing pin on the L7 coil (see digi shot) is this normal for the mk2 as my mk1 has 2 pins for L6 and L7?. Cant get any readings from the stump of the missing pin (maybe just a dummy). On the mk 1 chassis C9 goes across the two pins on L7 then to the anode of V2.
Graham.

taipai_royal · 10th Sep 2007, 10:14 pm

Quote:

Originally Posted by taipai_royal

Further progress has been hampered by a blown EF80, whilst waiting for a replacment I took a chance to check out the chassis wiring and recap routing. Looking under the reciever unit I noticed a missing pin on the L7 coil (see digi shot) is this normal for the mk2 as my mk1 has 2 pins for L6 and L7?. Cant get any readings from the stump of the missing pin (maybe just a dummy). On the mk 1 chassis C9 goes across the two pins on L7 then to the anode of V2.
Graham.

That should read "as my mk 2 has two pins each for L6 and L7?."

PJL · 11th Sep 2007, 12:32 am

The one service sheet I have and all I need is a TV22 to go with it...only 3 pins, pin 6 is common, 1 is L7 and 4 is L6.

taipai_royal · 11th Sep 2007, 7:17 am

Thanks PJL, that confirms it, the fourth pin as used on the MK 1 is a dummy just used as a carrier post for C9 to V2 anode.
Graham.

taipai_royal · 16th Sep 2007, 10:57 pm

Found it, the cause of the sound fault, during the recap I had coupled up C38 earthy end to the heater pin on V11,talk about numbskull, now I have good sound reproduction with no hum. Thanks to everyone for your help,still got a bit of fine tuning and tidying up to do, will keep you posted.
Grham.

6th Sep 2007, 9:28 pm	#21
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Bush TV22 MK 11 Restoration Update I hope we're all working off the same diagram! For me, Trader Sheet 1091. If it's a different one, let me know! The part numbers are different.... C52 on my diagram is the one that feeds the volume control. Anyway, first, tune for a perfect picture. Then check C10 and try a tweak of L6. This is adjacent channel sound rejection. The sound IF is taken off by L12/R13. Also check L25 and L27. Hope this helps! Cheers, Steve P __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?

7th Sep 2007, 7:33 am	#22
taipai_royal Pentode Join Date: Apr 2003 Location: Didcot UK Posts: 121	Re: Bush TV22 MK 11 Restoration Update Thanks Steve, C10 does not measure up to its spec,being low value is it safe to temporary remove, no improvement with adjusting L6, I will try tweaking L25/27?. Graham.

7th Sep 2007, 9:30 am	#23
Ian - G4JQT Octode Join Date: Jun 2004 Location: Reading/Fakenham, UK. Posts: 1,326	Re: Bush TV22 MK 11 Restoration Update Have you tried injecting some audio into the grid of the audio valve to see if the AF ccts are working properly? If you have the equipment (or can borrow) 19.5 MHz with some mod straight into pin 2 of V3 (Bush service sheet numbering) bottom chassis to see if the sound IF is working. I shouldn't tweak anything just yet unless it's obvious someone has been there before! Ian

7th Sep 2007, 10:00 am	#24
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Bush TV22 MK 11 Restoration Update Change C10, Don't try to line a circuit up with parts missing!! Cheers, Steve P __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?

10th Sep 2007, 9:09 pm	#25
taipai_royal Pentode Join Date: Apr 2003 Location: Didcot UK Posts: 121	Re: Bush TV22 MK 11 Restoration Update Further progress has been hampered by a blown EF80, whilst waiting for a replacment I took a chance to check out the chassis wiring and recap routing. Looking under the reciever unit I noticed a missing pin on the L7 coil (see digi shot) is this normal for the mk2 as my mk1 has 2 pins for L6 and L7?. Cant get any readings from the stump of the missing pin (maybe just a dummy). On the mk 1 chassis C9 goes across the two pins on L7 then to the anode of V2. Graham. Attached Thumbnails

11th Sep 2007, 12:32 am	#27
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	Re: Bush TV22 MK 11 Restoration Update The one service sheet I have and all I need is a TV22 to go with it...only 3 pins, pin 6 is common, 1 is L7 and 4 is L6.

11th Sep 2007, 7:17 am	#28
taipai_royal Pentode Join Date: Apr 2003 Location: Didcot UK Posts: 121	Re: Bush TV22 MK 11 Restoration Update Thanks PJL, that confirms it, the fourth pin as used on the MK 1 is a dummy just used as a carrier post for C9 to V2 anode. Graham.

16th Sep 2007, 10:57 pm	#29
taipai_royal Pentode Join Date: Apr 2003 Location: Didcot UK Posts: 121	Re: Bush TV22 MK 11 Restoration Update Found it, the cause of the sound fault, during the recap I had coupled up C38 earthy end to the heater pin on V11,talk about numbskull, now I have good sound reproduction with no hum. Thanks to everyone for your help,still got a bit of fine tuning and tidying up to do, will keep you posted. Grham.