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    Motorola MJE243/ 253 in NAD 3140

    I'm working on a NAD 3140 integrated that uses these transistors as drivers for the power amplifier. Some of its outputs have failed and, while the drivers test well and consistently on an atlas DCA, I'm weary as I don't have a curve tracer to fully verify their operation in circuit. I've heard...
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    Can I replace this 3.3µF electrolytic capacitor with a 1µF film?

    I'm recapping a Technics SL-P555 CD player and I've run out of 3.3µF WIMA MKS2 film caps for C809 and C810. However, I have most values 2.2µF and under as either MKS2 or R82. As C809 and C810 are in the audio path, might the better dissipation factor and DC leakage specs of film permit using a...
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    Technics SVI4003/ SVI4004 production change causing failure?

    I've seen around 10 examples of amps using SVI4003 and SVI4004 'current drive' power amplifier chips, a number of which having severe damage with transistors blown apart and resistors burnt to crisps etc, which I believe are cascading failures originating with shorts inside the SVI IC's...
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    Vintage CD players are a pain

    Vintage CD players are such a pain in the a$$. I've sold a good number over the years after servicing them and they're the only type of equipment I've ever had complaints about, weeks or months after initial satisfaction from the buyer or owner. Only a few, but that's enough for me given the...
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    PCB connector help

    I have a 4 terminal PCB connector from a 1990's Technics CD player that requires replacing. Can anybody advise a suitable replacement available on DigiKey preferably? The original part number is RJS1A1704. It accept bare wire and has a bracket that clamps down on the wire and has to be pushed...
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    Shure M35X broken body?

    I have 2 Shure M35X cartridges here that have separated into 2 pieces. Upon first glance it seems like the cartridge is merely glued into a plastic shell. I have already glued them once but they have broken again after a couple of months sitting on the shelf. The first attempt was with hot...
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    2SA1306/ 2SC3298 replacements required. No dice...

    Are there any readily available substitutes for this pair? They have a very high fT. The datasheets boast this as a primary feature, but simultaneously state the part is designed for power and driver amplifier applications. Why would such a high fT be necessary for a power amplifier...
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    2SA1667/ 2SC4381 for 2SA1306/ 2SC3298

    These Sankens over at Digi-Key look like great replacements for the older Toshibas. Does anybody have any experience with them?
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    NAD 3020 Phono input capacitors C401/ C402

    I have run out of 4.7µF capacitors, but I have 3.3 and 6.8µF. It'll be a while before I order more components and these two capacitors are the only ones in the way of completion. How critical is this value? Must I go out of my way to get 4.7µF? If not, would it be better to use the 3.3 or the...
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    Technics SU-V550 bias setting

    I'm trying to set the bias according to the service manual, to 50mV, but the value decreases by about 10mV rather than increasing to 60-85mV as specified in the service manual. The bias was at 30mV when I first got it. Is the service manual correct? I suspect it is not. It's like it's supposed...
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    Untraceable issues driving me insane...

    I think my electronics knowledge would best be described as intermediate. I know all different types of component, DC vs AC, how to take voltage measurements on a board, how to test & install components, how to be cautious, and I have excellent soldering/ work skills. I do not have a curve...
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    NAD 3020 TO-3 heatsink insulation grommets/ bushings

    Does anybody know if replacements for the tiny insulation bushings that sit in the screw holes for the TO-3 devices are available? All I can find are flanged ones, which are unsuitable.
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    How to do NAD 3020 Series 20 idle current adjustment???

    I'm feeling a lot of confusion in trying to figure out how to do the bias adjustment on my early unit with loads of 47µF caps, the power supply daughter board and filter caps near the headphone jack. I've done lots of work on it but trying to ascertain how to do the bias adjustment is stressing...
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    2N6551/ 2N6554 replacements

    For the sake of convenience and keeping everything as tidy as possible, is there a substitute for these available with the same pinout? (EBC)
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    SPST power switch for UK spec NAD 3020 Series 20?

    It's impossible to find a replacement DPST 'plunger for cap' switch to replace the original in these units. I can't find one in stock anywhere. The DPST switch allows live and neutral to be switched at the same time, but I have seen many amplifiers from other brands and that are much younger...
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    Technics SU-V45A/ SU-V series power transformer fuse

    I have an SU-V45A here with an open transformer. Does anybody know where the internal fuse is located and how to get to it? The schematic states there is one. I imagine its location would be the same in any 1980's SU-V transformer.
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    How to remove SL-1600 MK2 arm motor gears?

    How do you remove the gears from the arm drive mechanism of this turntable? The smaller one needs to be replaced and everything is stuck fast.
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    Technics SL-P220/ 320/ SOAD32A switch problem?

    I have a P220 here with a weird problem and a common problem and I think the 2 are related. The weird issue is that the eject button is completely unresponsive unless I push the rack gear forward very slightly. The more common one is that it will not spin up. The issue seems similar to that...
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    Technics SU-V85A disassembly

    I'm trying to disassemble a Technics SU-V85A, but the service manual is useless. I can't undo connector J10. It's a type I haven't seen before and I'm getting nowhere with it. I tried prying and the front part broke off. The ribbon still will not come out. How does this thing release...
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    Philips CDM12 sled rail lubrication

    CDM 12 by TommyTomTom posted Oct 9, 2021 at 3:16 PM I need to re-lubricate the sled rails in this CDM12.1 mech, but the laser assembly appears completely stuck and I can't slide it. The are 2 metal contacts right next to the spindle motor. There seems to be a little plastic catch hanging over...
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    NAD 3020 Series 20 tone control potentiometers

    The 2 10 kOhm dual ganged potentiometers for the tone controls of this NAD amplifier appear to be bad. They're 16% out of tolerance at approx. 8.4 kOhm each. That doesn't seem too bad, but... If I centre the pots and measure from each outside lead to the centre, 1 side measures approx 7.1 kOhm...
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    Technics SL-D303 - Untraceable short circuit.

    This is the most bizarre electronic fault I've ever seen. The unit powers on, but will not rotate. I found that the motor on/ off SPDT Microswitch S1 was shorting instead of switching, but working fine out of circuit. 2 more switches confirm it is not the switch that's at fault. Next, I...
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    Technics SL-P555 won't turn on

    I'm absolutely terrified right now. I just finished getting my silver SL-P555 in top order by installing a new tray belt. All was well. I then went to remove the top cover to look at the belt running, just to make sure it was perfectly seated and all, but the unit shut down immediately and now...
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    Warped dust covers

    I have a dust cover here with a minor dip across the top, from the middle, and the front fascia is pushed out slightly, looking 'bowed'. It's probably had a plant on it for a decade or something... The cover requires restoration, and it's really difficult to work on properly with this dip...
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    Vintage Technics Direct Drives - serious spindle bearing issue

    I have recently happened upon a serious issue affecting every and all vintage Technics Direct Drive models. As you may know, running these units without oiling the spindle/ bearing leads to scoring and damage that severely increases rumble and, in more severe cases, an audible scraping noise as...
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