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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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10th Sep 2017, 7:23 pm | #1 |
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Bush DAC90A Rescue
Hi,
I've recently acquired a DAC90A that looks like it had spent the 60s and 70s in a chippy judging by the amount of grease inside the cabinet. It briefly lit the bulb on my safety lamp but I was only greeted with a fizzing (electrical type!) sound. I wasn't expecting much anyway. The cabinet looks like it's had a regular brush with a Brillo pad - possibly to remove chip fat so I'll have to see just how good I can get it to look with some TLC. On the plus side there are no chips (no pun intended) or scratches. I'm going through the usual wax cap replacement and had found that the output primary is very high (MegaOhms). I've searched this forum and I believe forum member Ed Dinning does transformer rewinds, I'd rather do this route than use a Universal from RS if possible. I already have another DAC90A, VHF62 and an Ekco U353 all in working order and regular use. Thanks Steve |
10th Sep 2017, 7:36 pm | #2 |
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Re: Bush DAC90a Rescue
See post number 3, perhaps a PM to Ed.
https://www.vintage-radio.net/forum/...d.php?t=139694
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Frank |
10th Sep 2017, 8:01 pm | #3 |
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Re: Bush DAC90a Rescue
Thanks, I wasn't sure if it was good etiquette or not to land here as a newbie and PM somebody.
Thanks Steve |
10th Sep 2017, 8:15 pm | #4 | |
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Re: Bush DAC90a Rescue
Hello and welcome, Steve.
These are nice sets and restore easily on the whole, just beware of the potentially live-chassis design. Quote:
N. |
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10th Sep 2017, 8:30 pm | #5 |
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Re: Bush DAC90a Rescue
Ed may well post to this thread.
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11th Sep 2017, 9:04 pm | #6 |
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Re: Bush DAC90A Rescue
Hi Gents, seen done and another customer hopefully satisfied.
Ed |
11th Sep 2017, 9:24 pm | #7 |
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Re: Bush DAC90A Rescue
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18th Sep 2017, 1:43 pm | #8 |
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Re: Bush DAC90A Rescue
Thanks to Ed Diining there is now a nice refurbed transformer in place. Some of the feed wiring was a bit crusty so I've replaced that too. Looks good now - to me anyway
I'm just waiting for delivery of some 18 SWG heat resistant wire for the connections to the dropper. I'd noticed on the dropper that there is a single take off from the 210v tap going to R16 - is this correct? I was going to replace both Tone Correction caps with standard items but reading some other threads would suggest different values to reduce HF roll off. My other DAC90a certainly sounds muddier than my Ekco U353. Thanks Steve |
18th Sep 2017, 3:45 pm | #9 |
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Re: Bush DAC90A Rescue
Have a read of this thread: https://www.vintage-radio.net/forum/...ad.php?t=35784
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18th Sep 2017, 5:27 pm | #10 |
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Re: Bush DAC90A Rescue
The modifications suggested by Kaylee make a big difference. I would suggest that you critically examine and listen to the speaker preferably with another sound source first.
They are an odd speaker and do suffer from loose suspension and dirt in the pole gap. Sam. |
18th Sep 2017, 7:50 pm | #11 |
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Re: Bush DAC90A Rescue
Hi Steve, safest way is to get it working first, then do the mods and be amazed at the difference.
Ed |
18th Sep 2017, 9:17 pm | #12 |
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Re: Bush DAC90A Rescue
If you replace the tone corrector capacitors, you might as well put the modified values in straight away. But anything else - get it working first, and then have a play.
Good luck! |
19th Sep 2017, 10:20 pm | #13 |
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Re: Bush DAC90A Rescue
Thanks very much. I shall return with an update soon.
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27th Sep 2017, 7:31 pm | #14 |
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Re: Bush DAC90A Rescue
Hi
I've replaced the dropper wiring with heat resistant 18SWG. I've read the thread by Kaylee and I think I understand what I need to do but I'll have to order the correct caps to do the job. There are some rectangular brown caps C3, C6, C2 etc any special requirements for these? Once this has been done I think it's just a matter of checking and powering up!! |
27th Sep 2017, 8:08 pm | #15 |
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Re: Bush DAC90A Rescue
Any small value square caps are mica, very rarely defective and replacing them can muck up the alignment, best left alone until proven otherwise.
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27th Sep 2017, 9:14 pm | #16 |
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Re: Bush DAC90A Rescue
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