Hi,
I've got a few vintage Denon direct drive turntables that I'm going to sell in order to pay for a better model vintage Denon direct drive turntable that I just bought. I'd like to do whatever I can to maximize the value of the ones I'm selling and have noticed some TTs listed as "recapped and refurbished" have done well on eBay. If I could replace a number of old capacitors in the TT for $20- $30 to make it more reliable in the long term and get say $100 more for the TT, I'd be willing to do it.
My question is, what caps should I look at swapping out to increase the long-term reliability of the TT? The motor control unit capacitor? The servo amp unit capacitors? The power supply capacitor? Which caps are the ones that fail most often?
I talked to a local vintage audio shop that refurbishes and services vintage TTs before they resell them and they told me they generally don't like to mess around with any components having to do with the quartz locking speed control if it's working okay already as doing so can create problems that you didn't have before.
What caps would you recommend I swap out if any? What about transistors or resistors?
I've got a few vintage Denon direct drive turntables that I'm going to sell in order to pay for a better model vintage Denon direct drive turntable that I just bought. I'd like to do whatever I can to maximize the value of the ones I'm selling and have noticed some TTs listed as "recapped and refurbished" have done well on eBay. If I could replace a number of old capacitors in the TT for $20- $30 to make it more reliable in the long term and get say $100 more for the TT, I'd be willing to do it.
My question is, what caps should I look at swapping out to increase the long-term reliability of the TT? The motor control unit capacitor? The servo amp unit capacitors? The power supply capacitor? Which caps are the ones that fail most often?
I talked to a local vintage audio shop that refurbishes and services vintage TTs before they resell them and they told me they generally don't like to mess around with any components having to do with the quartz locking speed control if it's working okay already as doing so can create problems that you didn't have before.
What caps would you recommend I swap out if any? What about transistors or resistors?
Although I have a JVC Ql-10 , the same issues apply.
Do you mess with it while it still works , or wait for something to go wrong to give you incentive to fix it..,
Also the old saying " if it ain't broke don't fix it " is better advice ?!
Maybe letting it run all day to electrically settle is a good idea once and awhile.
The way I would proceed ( haven,t yet ) is to replace stressed areas first ( power supply caps ) and then get a infrared laser thermometer and check other hot areas around caps and maybe do those next.
What would be worst thing to do is replace all caps and have it not work.
Slowly replace certain areas so you don't loose your way so you can go back to original if necessary maybe.
Unless you have a service manual and understand its adjustments, maybe just PS caps only.
I no nothing about locked speed circuits also and feel your pain
Regards
David
Do you mess with it while it still works , or wait for something to go wrong to give you incentive to fix it..,
Also the old saying " if it ain't broke don't fix it " is better advice ?!
Maybe letting it run all day to electrically settle is a good idea once and awhile.
The way I would proceed ( haven,t yet ) is to replace stressed areas first ( power supply caps ) and then get a infrared laser thermometer and check other hot areas around caps and maybe do those next.
What would be worst thing to do is replace all caps and have it not work.
Slowly replace certain areas so you don't loose your way so you can go back to original if necessary maybe.
Unless you have a service manual and understand its adjustments, maybe just PS caps only.
I no nothing about locked speed circuits also and feel your pain
Regards
David
Tricky question. If you have a 'name' in refurb then you can add value to the unit. However just randomly changing bits may not actually make the unit any more attractive.
I could do the power supply caps quite easily. On this one TT I'm working on right now (A Denon DP-1000 transport) there's just a single .047 uF ceramic capacitor on the power supply board that I could easily replace. What I'm wondering is if I should replace it with a similar ceramic cap or use another kind. Hopefully, someone more knowledgeable than me will chime in here.
On that same TT, there's also a single large rectangular box shaped 2.85 uF capacitor on the motor control board that would also be easy to replace. It looks a fair bit like a start capacitor but I'm wondering if hat's what it really is. If it helps, the only other thing on that board is a resistor.
Being a DD turntable, I'm suspecting that 2.85 uF cap might have something to do with speed regulation (like a run capacitor) and concerned that a replacement capacitor would have to be an exact match. If it does, replacing that cap with a single capacitor would be difficult as 2.85 uF seems to be a difficult capacitance to find. I guess I could get 2.85 uF by connecting a number of smaller caps in series. If a 3 uF cap could be used without messing up the speed control, it would be dead easy to replace that capacitor.
Does anybody know what that motor control board cap does on the Denon DP 1000 TT motor control board and if it has to be replaced by a cap with identical capacitance?
The Denons have relatively simple electronics in comparison to the DC direct drive models using the Matsushita patent (all DD tables EXCEPT Denons). But be sure you're not going down the rabbit hole; a working Denon is worth a lot more than a non-working one, regardless of the age of the caps. Besides, the AC Denons always sell for a premium price in the first place; they didn't sell that many and the people who want them REALLY want them. Just set a proper reserve and BuyItNow price and a long sell period and the people who seek them out will find you.
The motor control cap would be doing the same thing any cap on any AC motor does.
Im sure you know this but I hate to see a good Denon go south, so for the sake of completeness, DO NOT touch, clean or stare furiously at the magnetic strip on the underside inside edge of the platter. Doing so runs the risk of making the motor assembly useless, and the only fix ... a replacement platter ... is unobtanium.
If it makes you feel any better, Ive never known a single instance of a Denon AC motor failing, save for the idiot move mentioned above, which comes up regularly on eBay as naive people "clean up" the table for photos. Telltale sign is they report the "motor works but spins at high speed". And it will continue spinning at high speed for the next thousand years, but don't expect to play any vinyl on it.
If the caps pass a visual inspection, the 'table keeps speed, and if you have the tools passes a few cap tests, I'd be inclined to leave 'em. Personally, I would never buy a re-capped AC DD Denon; I would only look at working tables that had not been touched by anyone. YMMV
The motor control cap would be doing the same thing any cap on any AC motor does.
Im sure you know this but I hate to see a good Denon go south, so for the sake of completeness, DO NOT touch, clean or stare furiously at the magnetic strip on the underside inside edge of the platter. Doing so runs the risk of making the motor assembly useless, and the only fix ... a replacement platter ... is unobtanium.
If it makes you feel any better, Ive never known a single instance of a Denon AC motor failing, save for the idiot move mentioned above, which comes up regularly on eBay as naive people "clean up" the table for photos. Telltale sign is they report the "motor works but spins at high speed". And it will continue spinning at high speed for the next thousand years, but don't expect to play any vinyl on it.
If the caps pass a visual inspection, the 'table keeps speed, and if you have the tools passes a few cap tests, I'd be inclined to leave 'em. Personally, I would never buy a re-capped AC DD Denon; I would only look at working tables that had not been touched by anyone. YMMV
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