Bush DAC90A FM Conversion - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

bobhowe · 29th Oct 2021, 6:04 pm

Good progress today installed the board on the chassis this afternoon as this is going to be a FM Set only this conversion is different to David Boynes set as he is retaining MW & LW . Changed the tuning capacitor for a one that I have cleaned in Methylated Spirits and the results are Excellent as the board is properly grounded to the chassis next step is to fit the ED Dinning Auto Transformer and an Aerial socket going to order another board of David Winter for a Future project hears some pictures of progress now

FERNSEH · 29th Oct 2021, 9:12 pm

Hi Bob,
fit Ed's transformer and you've got your supply voltage for the FM module. Rectified and smoothed the 6.3volt dial lamp tap will provide well over 6 volts DC. An added bonus a reduction of heat inside the cabinet.
I'm satisfied the Lorlin switch now has plenty space to accommodate all the extra wiring so will go ahead modifying the spare DAC90A chassis.

DFWB.

bobhowe · 29th Oct 2021, 10:06 pm

Hi David been listening to Radio 2 Classic FM Metro Radio Sun FM Radio Newcastle and more now spoilt for choices of stations to listen on a DAC90A

. Next step as you have you said is the Ed Dinning auto transformer and before signing of the conversion is to put a safe external Aerial socket and run it for a while with an external speaker in case there is any tweaks on the audio stage kind regards Bob

Gabe001 · 30th Oct 2021, 7:26 am

Quote:

Originally Posted by FERNSEH

Hi Bob,
fit Ed's transformer and you've got your supply voltage for the FM module. Rectified and smoothed the 6.3volt dial lamp tap will provide well over 6 volts DC. An added bonus a reduction of heat inside the cabinet.
I'm satisfied the Lorlin switch now has plenty space to accommodate all the extra wiring so will go ahead modifying the spare DAC90A chassis.

DFWB.

How are you going to access the switch when the chassis is in the case? Are you going to install a new knob?

FERNSEH · 30th Oct 2021, 10:27 am

Quote:

Originally Posted by Gabe001

How are you going to access the switch when the chassis is in the case? Are you going to install a new knob?

The new wavechange switch and knob will be in the same position at the side of the cabinet as the original two position MW/LW switch was.

DFWB.

FERNSEH · 30th Oct 2021, 11:49 am

The new waveband switch will have to be turned 90 degrees anti-clockwise so that flat on the shaft agrees with position for LW as it was with the original switch.

DFWB.

bobhowe · 30th Oct 2021, 1:49 pm

Hi David have you decided where to install the board?

FERNSEH · 30th Oct 2021, 2:54 pm

Hi Bob,
the best location for the FM module will be on the left side chassis bracket.
Close as possible to the switch in order to keep lead lengths as short as possible.

DFWB.

Gabe001 · 30th Oct 2021, 4:14 pm

Quote:

Originally Posted by FERNSEH

The new waveband switch will have to be turned 90 degrees anti-clockwise so that flat on the shaft agrees with position for LW as it was with the original switch.

DFWB.

Genius!

bobhowe · 30th Oct 2021, 4:24 pm

Hi David looking forward to see the switch wiring good idea to keep it short kind regards Bob

bobhowe · 31st Oct 2021, 9:03 pm

Further progress made today installed an Aerial socket with a 2 watt 1 meg resistor & a 1000pf class y capacitor for isolation & made the rectified DC circuit for the board using a 1N4002 diode & a 1000MF capacitor

murphyv310 · 31st Oct 2021, 10:49 pm

Quote:

Originally Posted by bobhowe

NEWS-FLASH looks what has arrived from France ( Very quick postage ) thanks David

Waiting for a anti static wrist band to arrive from the UK that is taking longer before I start to work on it

Hi.
I'm surprised it's not in an anti static bag or foam.

david winter · 1st Nov 2021, 9:55 am

Quote:

Originally Posted by murphyv310

Hi.
I'm surprised it's not in an anti static bag or foam.

It actually is, but was removed from it for the picture.

david winter · 1st Nov 2021, 9:59 am

Quote:

Originally Posted by bobhowe

Further progress made today installed an Aerial socket with a 2 watt 1 meg resistor & a 1000pf class y capacitor for isolation & made the rectified DC circuit for the board using a 1N4002 diode & a 1000MF capacitor

The board has a 1N5819 followed by a 1500µF capacitor.
Are you using your 1N4002 + 1000µF to make a voltage doubler ?

FERNSEH · 1st Nov 2021, 12:10 pm

Quote:

Originally Posted by FERNSEH

The new waveband switch will have to be turned 90 degrees anti-clockwise so that flat on the shaft agrees with position for LW as it was with the original switch. DFWB.

That job was done on Saturday. The switch is now positively located by the dowel pin. See pic.

DFWB.

bobhowe · 1st Nov 2021, 3:28 pm

Hi David looks like a factory job

bobhowe · 1st Nov 2021, 3:31 pm

Quote:

Originally Posted by david winter

Quote:

Originally Posted by bobhowe

Further progress made today installed an Aerial socket with a 2 watt 1 meg resistor & a 1000pf class y capacitor for isolation & made the rectified DC circuit for the board using a 1N4002 diode & a 1000MF capacitor

The board has a 1N5819 followed by a 1500µF capacitor.
Are you using your 1N4002 + 1000µF to make a voltage doubler ?

Hi David forgot it had a diode and smoothing capacitor so I can use the 6.3v tap of the auto transformer

bobhowe · 1st Nov 2021, 7:03 pm

More progress today replaced the UL41 for a NOS UL44 and removed the mains dropper and fitted the Ed Dinning Auto Transformer . As David Winter pointed out the board has rectification diode and smoothing capacitor so I connected the board to the 6.3V AC tap on the Auto Transformer then the 117V tap to the valve heaters and the 205V tap to the UL41 250 ohm surge limiter resistor . Removed the dial lamp shunt resistor as it is not needed as the dial lamps are connected to the 6.3V tap as well . Connected the mains Neutral direct from the Neutral side of the switch to the chassis and Neutral on the Auto Transformer then the Live side of the switch to the Live connection on Auto Transformer . Set now performs great no hum or interference and I have been listening to Steve wright on radio 2 hear is some pictures before and after the Auto Transformer is fitted more to follow

mark2collection · 2nd Nov 2021, 4:38 pm

Many moons ago I found the attached (jpg) on the forum and cannot for the life of me remember who did the original artwork.

It was me who modified things from M/Cs to MC/s.

It'll need recalibrating since it only goes to 100

Would be nice if we can re-cal & ask that chap in Greece to run some off. I know you set is technically FM only now, but as dials go, it's a good starting point?

Looking good though Bob, I bet ya well chuffed.

Mark

bobhowe · 2nd Nov 2021, 5:11 pm

Quote:

Originally Posted by mark2collection

Many moons ago I found the attached (jpg) on the forum and cannot for the life of me remember who did the original artwork.

It was me who modified things from M/Cs to MC/s.

It'll need recalibrating since it only goes to 100

Would be nice if we can re-cal & ask that chap in Greece to run some off. I know you set is technically FM only now, but as dials go, it's a good starting point?

Looking good though Bob, I bet ya well chuffed.

Mark

Hi Mark thanks for the Kind comment I will be doing a 3 waveband DAC90A later . & FERNSEH is doing a 3 wave band DAC90A so it would be nice if you could find out if it can be recalibrated and and made that would be great .Yes I am well chuffed I have ordered another board are you going to get one Mark

29th Oct 2021, 6:04 pm	#21
bobhowe Heptode Join Date: Jun 2005 Location: Sunderland, Tyne and Wear, UK. Posts: 661	Re: Bush DAC90A FM Conversion Good progress today installed the board on the chassis this afternoon as this is going to be a FM Set only this conversion is different to David Boynes set as he is retaining MW & LW . Changed the tuning capacitor for a one that I have cleaned in Methylated Spirits and the results are Excellent as the board is properly grounded to the chassis next step is to fit the ED Dinning Auto Transformer and an Aerial socket going to order another board of David Winter for a Future project hears some pictures of progress now Attached Thumbnails __________________ Kind regards, Bob.

29th Oct 2021, 9:12 pm	#22
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Bush DAC90A FM Conversion Hi Bob, fit Ed's transformer and you've got your supply voltage for the FM module. Rectified and smoothed the 6.3volt dial lamp tap will provide well over 6 volts DC. An added bonus a reduction of heat inside the cabinet. I'm satisfied the Lorlin switch now has plenty space to accommodate all the extra wiring so will go ahead modifying the spare DAC90A chassis. DFWB.

29th Oct 2021, 10:06 pm	#23
bobhowe Heptode Join Date: Jun 2005 Location: Sunderland, Tyne and Wear, UK. Posts: 661	Re: Bush DAC90A FM Conversion Hi David been listening to Radio 2 Classic FM Metro Radio Sun FM Radio Newcastle and more now spoilt for choices of stations to listen on a DAC90A . Next step as you have you said is the Ed Dinning auto transformer and before signing of the conversion is to put a safe external Aerial socket and run it for a while with an external speaker in case there is any tweaks on the audio stage kind regards Bob __________________ Kind regards, Bob.

30th Oct 2021, 11:49 am	#26
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Bush DAC90A FM Conversion The new waveband switch will have to be turned 90 degrees anti-clockwise so that flat on the shaft agrees with position for LW as it was with the original switch. DFWB. Attached Thumbnails

30th Oct 2021, 1:49 pm	#27
bobhowe Heptode Join Date: Jun 2005 Location: Sunderland, Tyne and Wear, UK. Posts: 661	Re: Bush DAC90A FM Conversion Hi David have you decided where to install the board? __________________ Kind regards, Bob.

30th Oct 2021, 2:54 pm	#28
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Bush DAC90A FM Conversion Hi Bob, the best location for the FM module will be on the left side chassis bracket. Close as possible to the switch in order to keep lead lengths as short as possible. DFWB.

30th Oct 2021, 4:24 pm	#30
bobhowe Heptode Join Date: Jun 2005 Location: Sunderland, Tyne and Wear, UK. Posts: 661	Re: Bush DAC90A FM Conversion Hi David looking forward to see the switch wiring good idea to keep it short kind regards Bob __________________ Kind regards, Bob.

31st Oct 2021, 9:03 pm	#31
bobhowe Heptode Join Date: Jun 2005 Location: Sunderland, Tyne and Wear, UK. Posts: 661	Re: Bush DAC90A FM Conversion Further progress made today installed an Aerial socket with a 2 watt 1 meg resistor & a 1000pf class y capacitor for isolation & made the rectified DC circuit for the board using a 1N4002 diode & a 1000MF capacitor __________________ Kind regards, Bob.

1st Nov 2021, 3:28 pm	#36
bobhowe Heptode Join Date: Jun 2005 Location: Sunderland, Tyne and Wear, UK. Posts: 661	Re: Bush DAC90A FM Conversion Hi David looks like a factory job __________________ Kind regards, Bob.

1st Nov 2021, 7:03 pm	#38
bobhowe Heptode Join Date: Jun 2005 Location: Sunderland, Tyne and Wear, UK. Posts: 661	Re: Bush DAC90A FM Conversion More progress today replaced the UL41 for a NOS UL44 and removed the mains dropper and fitted the Ed Dinning Auto Transformer . As David Winter pointed out the board has rectification diode and smoothing capacitor so I connected the board to the 6.3V AC tap on the Auto Transformer then the 117V tap to the valve heaters and the 205V tap to the UL41 250 ohm surge limiter resistor . Removed the dial lamp shunt resistor as it is not needed as the dial lamps are connected to the 6.3V tap as well . Connected the mains Neutral direct from the Neutral side of the switch to the chassis and Neutral on the Auto Transformer then the Live side of the switch to the Live connection on Auto Transformer . Set now performs great no hum or interference and I have been listening to Steve wright on radio 2 hear is some pictures before and after the Auto Transformer is fitted more to follow Attached Thumbnails __________________ Kind regards, Bob.

2nd Nov 2021, 4:38 pm	#39
mark2collection Hexode Join Date: Jul 2010 Location: Royal Berkshire, UK. Posts: 471	Re: Bush DAC90A FM Conversion Many moons ago I found the attached (jpg) on the forum and cannot for the life of me remember who did the original artwork. It was me who modified things from M/Cs to MC/s. It'll need recalibrating since it only goes to 100 Would be nice if we can re-cal & ask that chap in Greece to run some off. I know you set is technically FM only now, but as dials go, it's a good starting point? Looking good though Bob, I bet ya well chuffed. Mark Attached Thumbnails __________________ Slowly turning the 'to-do', into 'ta-dah' Last edited by mark2collection; 2nd Nov 2021 at 4:43 pm.