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    Wondering if one of you wizards could help me identifying which transformer I need as per schematic?

    Hi Guys, someone here once helped me out big time by letting me know what type of transformer I needed to buy to replace a dead, impossible to find one in a pioneer receiver. I now have a TASCAM audio console with a dead power transformer and couldn’t find any specs anywhere. The schematic...
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    Pioneer SX-636 - wrong capacitor Value in Power Supply - advice needed

    Hi, I'm sitting here almost finishing recapping / re-transistoring my SX-636 and I'm down to the last couple caps - then I come across a capacitor which seems way off. According to the service manual and the recap shopping lists available on this forum - C12 on the power supply board is...
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    Using a single amplifier output to connect to both a speaker and a line level converter?? ohms??

    Hi, Ive got an interesting idea that I wanted to run past people with more expertise than me. On one of my systems - I have an amplifier with two sets of speaker outputs (A and B). on this system I run my Speaker A outputs to my speakers - and my Speaker B outputs to a "speaker level to line...
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    power transformer questions

    Hi, I'm by no means an electronics expert, but I have managed to do a fair bit of fixing work on my own equipment in the past, however , i'm not experienced with power transformers. I just stumbled across a Pioneer A-5 amplifier which is completely dead (wont power on). I put my multimeter on...
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    NAD 4240PE - no voltage drop across Emitter resistor?

    i am close to finishing a repair on a NAD 3240pe amplifier that I acquired. I've so far replaced 15 components in the right channel. Every one of the heatsink mounted transistors were shorted as well as a few of the non heatsink mounted ones, I also had 4 shorted diodes and a number of...
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    HA1452 IC in Pioneer SA5300

    Hi, I've been breathing life back into an old SA5300 integrated amplifier. I'm at a point where the amp is very nice cosmetically and works beautifully apart from the phono stage. The amp has been fully recapped and had all transistors replaced and I believe that it needs to have the HA1452...
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    Zener Diode Replacement

    hi, I need to replace a shorted UZ-15BL Zener Diode. I have experience with replacing these diodes. Is it ok to just another 15v Zener Diode - or do I need to match over specs as well? The only local store in my small town that sells components has a 14744 1 Zener Diode. Both diodes are 15v...
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    Connecting Active Subwoofers to Vintage Receivers

    hi all! So the concept has definently been spoken about in the past. But I'm exploring the best possible way to connect an active subwoofer to vintage receivers. The main issue I have identified by looking at schematics is that the "Tape output" on most of these old receivers is a very simple...
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    2SD669A replacement

    hi, So I need to replace 4x 2SD669A transistors in my NAD 3240PE Can someone please let me know if the KSC2690A Is a suitable replacement Cheers
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    Pioneer Rondo 3000 strange mono issue

    hi, I have a pioneer rondo 3000 stereo reciever with a strange issue. It's playing in mono. If I connect an RCA cable to either the L or R input (not both at the same time) - I get sound equally out of both speakers! The balance control still works as it should and this problem occurs on...
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    Pioneer SA5300 strange rapid "beating" noise from the speaker terminals

    Hi guy's, This has me stumped, I have a pioneer SA-5300 which was not working at all. I replaced all the transistors and brought it back to life somewhat. But I'm at a point where the amp is just putting out a loud rapid "beating" noise. I've discovered that I can make the noise stop as I'm...
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    STV3H 60B?

    hi, Is this what an STV3H normally looks like? What does the "60B" stand for?
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    Bleed between inputs?

    Hi guy's I'm trying to fix a Pioneer Rondo 2000 (no schematic or service manual available online). There is significant bleed from the Tape input onto all the other inputs (ie - if I have an audio source connected to the tape input and then move the input select switch to phono or the tuner...
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    Nichicon KA series caps

    I'm currently selecting capacitors for a recap job and wondering if anyone can explain this for me. If I look at range of Nichicon FG (fine gold series), I notice that each cap will have a voltage rating (eg: 16v, 25v, 100v etc). But looking at the KA series - instead of each cap having a...
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    Adjusting Bias on Reciever with no Trim Pots?

    I've almost got my pioneer Rondo 3000 back to 100% working order. I was measuring the voltage across the Emitter resisters and found that while the Resistors on the Right channel measure about 10mv each - the resistors on the Left side were only measuring about 2mv or less. In the schematic...
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    2SC281 replacement confusion

    Hi, I've accidentally snapped the leads off a 2SC281 transistor (didn't realise how famously fragile they are until I googled afterwards). I've been reading a lot of discussions about suitable replacements , but I've noticed that none of the replacements I've seen are of a heat sink mounting...
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    Transistors and Distortion

    Can a (bad) transistor itself cause distortion (assuming that the rest of the circuit is in good worker order). Or would would another component have to amplify the signal too much beforehand for the transistor to saturate the signal as it passes through?
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    Pioneer Rondo 3000 distorted output

    Hi guy's, This is somewhat of a "part 2" thread about the repair of my pioneer Rondo 3000 reciever. For anyone interested - the first part is here - http://audiokarma.org/forums/index.php?threads/15v-dc-on-the-speaker-outputs.755252/ I'm starting a new thread as not only is this a seperate...
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    Complimentary Transistors

    Hi, I have a question about pairing transistors. Am I correct in assuming that it is best to buy 2 versions (NPN and PNP) with matching specifications? Or is it just the DC current gain (HFE) that matters the most. I've ordered some BC33740BU transistors to replace a couple 2SC1213A...
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    15v DC on the speaker outputs

    hi guys, I've got a Pioneer Rondo 3000 reciever with an issue (or two lol). I recently purchased the reciever of someone on the local classifieds for cheap because it had 'no sound output'. I opened it up to find that both the fuses were blown on the outputs (not the main fuse for power). I...
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    Pioneer Transformer help!

    Hi guys, I have an old Pioneer SX-408 Reciever that has a dead power transformer. I'm having trouble finding any specs of the transformer to buy a suitable replacement. I was wondering if anyone would mind having a look at the schematic for me (available here...
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    NAD 7020e help...

    Hi guys, I was given a NAD 7020e from someone because it didn't work. I opened it up and replaced a couple blown fuses, turn it on and it still didn't light up. However - I connected speakers and found that the amplifier is completely working! It's just that the LED display on the front...
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    Help! Transister Hunting

    Hi guys, I have a Pioneer A20 Integrated amplifier from 1985 (not to be confused with the newer elite series A20). I have an issue where - after sitting for a while - turn the amp on, and then after a few seconds I hear the 'click' of the relay. The amp then works fine for a maximum of about 2...
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    Pioneer SPL-100 , help needed

    Hi Guys, First post here and I apologize if it's against the rules in anyway. I'm restoring an old Pioneer SPL-100 turntable and I cannot find a service manual anywhere. Does anyone have a copy of this manual. DISCLAIMER: yes - I'm talking about the "SPL-100" - NOT the "PL-100" Cheers!
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