cafe latte Posted August 1, 2021 Posted August 1, 2021 (edited) My passion for hifi started when I was about 14, I had my own hifi before that, but I remember a trip to a younger work friend of dads Keith who was about 15 years older than me and bit younger than dad. He had a Linn but dont recall the rest, the joke for years was my response at hearing his hifi, I declared it was like listening with headphones Keith ended up a good friend when I grew up and I fixed his Conrad Premier 4 which 3 repair shops had attempted before and failed. When Keith passed away a few years ago he left me it along with the Premier 3 preamp, what a mission to get a 40kg amp shipped from the UK, but it is a good memory of a friend.. Anyway that was the start of my path, my passion is why I learned electronics, basically to build my own amps which I designed and built even etching the boards, this passion led me to retip, also led me to learn everything I could about how it all worked, how to wind coils, build speakers, repair turntables no matter how complex, all has been very useful in my non hifi life as these skills mean I can fix most things and rarely get beaten, then there was the free DP3000 Denon direct drive I got from a friend... Wow this was frustrating, I replaced the caps first and set and cleaned the head tried it and speed jittered and it slowed and speeded up.. I tested all the transistors, which were fine but I replaced them just in case again to no avail. Next I ordered a new timing IC and the new one changed nothing, the psu measured perfect, I was out of options, totally beaten, it was testing fine but still not working why??? I disconnected it and moved on, 12 months passed and it sat mocking me on my hifi shelf. A recent Denon thread made me connect it again and I fired her up and the same annoying speed stability issue was still there, grrrr, I rarely loose my temper but I did that day and it helped too.... I stabbed hard at the off button in frustration and missed as the turntable is on the lower shelf which is harder to reach, my finger hit hardish on the 33 on button and to my shock the speed stabilized!!!! It was the darn switch!!!! It is like fixing a car when it is out of petrol!!! How could I miss such a simple thing, the symptoms make total sense as the switch was not making a good connection so simple, groan... Anyway it is spinning, and far from my best turntable but loving it for its faults. Moral is dont over look the obvious. Chris Edited August 1, 2021 by cafe latte 11 1
mkaramazov Posted August 1, 2021 Posted August 1, 2021 (edited) Great tale. I have been considering one of these motors, but also preparing myself for the complete service that will be required! Edited August 1, 2021 by mkaramazov
cafe latte Posted August 1, 2021 Author Posted August 1, 2021 20 minutes ago, mkaramazov said: Great tale. I have been considering one of these motors, but also preparing myself for the complete service that will be required! If you do check the switch first 1
josh0571 Posted August 1, 2021 Posted August 1, 2021 Very cool story Chris. What have you compared your DP3000 with? I have a DP80 which replaced a LP12. The build quality on these big Denon direct drives is awesome. They are solid, stable and retrieve great detail out of the disc. Don't think I'd go back to a belt-drive in a hurry! 2
cafe latte Posted August 1, 2021 Author Posted August 1, 2021 3 minutes ago, josh0571 said: Very cool story Chris. What have you compared your DP3000 with? I have a DP80 which replaced a LP12. The build quality on these big Denon direct drives is awesome. They are solid, stable and retrieve great detail out of the disc. Don't think I'd go back to a belt-drive in a hurry! Mine is not high up the range, but still returns (properly measured not a phone) wow and flutter of 0.03% which is very very respectable indeed. Chris
josh0571 Posted August 1, 2021 Posted August 1, 2021 1 minute ago, cafe latte said: Mine is not high up the range, but still returns (properly measured not a phone) wow and flutter of 0.03% which is very very respectable indeed. Chris I'm no expert, but that's a very decent read for sure!
cafe latte Posted August 1, 2021 Author Posted August 1, 2021 2 minutes ago, josh0571 said: I'm no expert, but that's a very decent read for sure! Now I have to find somewhere else to put the Commonwealth and the SP10mk2 I am rebuilding, the Denon was going to loose its spot relegated in disgrace for its misbehaviour, but seems it has had a last minute reprieve Chris
josh0571 Posted August 1, 2021 Posted August 1, 2021 1 minute ago, cafe latte said: Now I have to find somewhere else to put the Commonwealth and the SP10mk2 I am rebuilding, the Denon was going to loose its spot relegated in disgrace for its misbehaviour, but seems it has had a last minute reprieve Chris Haha and that is very tough competition coming from those two decks!
cafe latte Posted August 1, 2021 Author Posted August 1, 2021 12 minutes ago, josh0571 said: Haha and that is very tough competition coming from those two decks! Yes need more shelves Chris
cafe latte Posted August 1, 2021 Author Posted August 1, 2021 Been a lesson though this Denon how not to overlook the obvious and assume nothing. The Conrad Premier 4 I actually fixed twice for my friend, the second time was close to the end when he decided to bias the valves after his "special" not exactly legal medicine for his cancer (now legal for this sort of terminal patient). Anyway his self medication meant he was not in ideal state to bias valves and not using a metal screw driver for sure. He shorted the HT to low voltage BANG!!!! This time I replaced blown stuff but valves still kelp going into runaway, why??? I recheck the circuit again and again and kept seeing the Op amps and dismissing them and moving on, my mind was saying yep Op amp nothing to do with this issue. When I finally removed my blinkers Op amps can be used for valve bias circuit not just amplification, without the Op amp the valve just wanted to go into runaway. Why I think fixing stuff it is often a good idea to walk away when it is not going well as a fresh approach hopefully you follow different breadcrumbs Chris
audiofeline Posted August 1, 2021 Posted August 1, 2021 This story brings to mind when I left home, and the boyfriend of a housemate was a trainee tech at Telecom, and was always at our home. He taught me quite a lot about basic electronics and hifi. I recall he was frustrated for weeks trying to diagnose a problem he had in a piece of equipment he was building (possibly a graphic eq). All his trouble-shooting went nowhere. With an equal blend of Oblique Strategies and sarcasm I suggested that he had put a component upside-down. Turns out he had installed a capacitor the wrong way around, so my diagnosis was very close. 2
cafe latte Posted August 1, 2021 Author Posted August 1, 2021 5 minutes ago, audiofeline said: This story brings to mind when I left home, and the boyfriend of a housemate was a trainee tech at Telecom, and was always at our home. He taught me quite a lot about basic electronics and hifi. I recall he was frustrated for weeks trying to diagnose a problem he had in a piece of equipment he was building (possibly a graphic eq). All his trouble-shooting went nowhere. With an equal blend of Oblique Strategies and sarcasm I suggested that he had put a component upside-down. Turns out he had installed a capacitor the wrong way around, so my diagnosis was very close. Really easily done it just takes a moment of poor attention. I was doing the pays the other day at the fire station, I put 1400 (2pm) in the wrong box when someone was talking to me and it went into actual hours worked opps Nearly a huge pay for everyone, fortunately the massive pay error was easily spotted before we sent it off. Chris 1
cafe latte Posted August 15, 2021 Author Posted August 15, 2021 Bleeping thing.. Update, I was listening to it the other evening, record finished and I turned the record over and lowered the stylus and started walking back to my chair and suddenly hyper speed record, I just made it back to the record before there was a record frisbee and before stylus ripped off with the speed. There were a few choice words spoken as you can imagine. I tested the board and removed and tested a few transistors and then saw a dry joint, still misbehaving I replaced timing chip as hard to test it and then I was able to get it to work, but after 5 minutes it again went into hyper speed. Stopping it and restarting fixed it for another 5 minutes. Sunday so I got my soldering iron out and reflowed the whole board and half an hour later no issues fingers crossed this time all good. Bleeping thing.. Chris
cafe latte Posted August 15, 2021 Author Posted August 15, 2021 Grr it misbehaved again but it showed me the problem, still switch issues it seems. It started to speed up so I slowed it then it sped up and slowed. I switched to 45, then back to 33 and it would not switch back the 45 light stayed on no matter what I did. I wacked the 33 and it went back to 33 and stable so the 33 button is having issues. I gave the 33 a good thump (not going to keep doing this just experiment) and so far so good again I hope.. Chris 1 1
cafe latte Posted August 15, 2021 Author Posted August 15, 2021 It has now been good since so clearly a switch or possibly relay issue, but just going to enjoy it today. Chris
josh0571 Posted August 15, 2021 Posted August 15, 2021 Geez Chris, you're copping some direct drive switch grief. Hope it's settled down now!
cafe latte Posted August 15, 2021 Author Posted August 15, 2021 2 hours ago, josh0571 said: Geez Chris, you're copping some direct drive switch grief. Hope it's settled down now! It is one of those gremlin faults, seems it cools and for 5 mins it has some issues then it is spot on. I had dinner and it had a little issue and then good and when good stays good (listening to it now). My guess is resistance is changing from cold to warm not sure where though and this is causing the drift. Next try is to wire in a fine adjust pot with long wires to eliminated that. When it is finally fixed it should work for a long time as almost everything on the board is new Chris 1
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