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power supply

  1. tusntuk2

    Could use some help on a +B Power Supply problem in a Kenwood KR-5600

    I'm restoring a Kenwood KR-5600 that was in working condition, at least I know the FM and the Tape inputs were working, and I started with the power supply. The KR-5600 has a history of heat problems with its design, so I boosted the clumped resistors to 3 watts and the caps to UPW 100/50v...
  2. tusntuk2

    Could use some help on a +B puzzle in a Kenwood KR-5600

    I'm restoring a Kenwood KR-5600 that was in working condition, at least I know the FM and the Tape inputs were working, and I started with the power supply. The KR-5600 has a history of heat problems with its design, so I boosted the clumped resistors to 3 watts and the caps to UPW 100/50v...
    • tusntuk2
    • Thread
    • 2630-10 fm muting kenwood kr-5600 phono ic's power supply rails recapping
    • Replies: 3
    • Forum: Solid State
  3. dyehardfan

    DC Power Supply Cable Pinout

    If I've posted this to the wrong forum, I apologize. I would very much appreciate it if someone could help me figure out which cable I need? Scenario - DC Linear Power Supply with center positive output. Technics SL-10 uses a center negative plug. I am looking at cables I have the option of...
  4. SmokedPorter

    CR-2020 Service Bulletins - Please Help

    I am not a technician and need advice on getting upgrades done on two CR-2020s. See “Background” below regarding the our two CR-2020s. Anything will be greatly appreciated. Thank you. A couple of days ago I dug out our two CR-2020 receivers to look further into the speaker protection relay...
    • SmokedPorter
    • Thread
    • advice cr-2020 electrolytic help needed power supply regulator transistors service bulletin yamaha
    • Replies: 6
    • Forum: Solid State
  5. David_NC

    Power Supplies -

    I've got access to a few power supplies like the ones shown below. These are 12V / 9A, 15V / 5A, and 24V (I can't recall the current rating). These are nice, industrial units that are in metal cases with removable input and output cords. They are a bit large, but have cords (vs vs being wall...
  6. tusntuk2

    Pioneer SX-727 Blown Internal Fuse - what can I do?

    Hello AK, thanks for looking in. I'm having trouble identifying the cause for blowing an internal 3A fuse (# 2) in a Pioneer SX-727. I have reviewed other threads here and made some changes to my unit, but the fuse blew again while on the DBT, so I'm stuck, now. Can't measure voltages if it...
    • tusntuk2
    • Thread
    • fuse blow pioneer power supply protection circuit sx-727 trimmers zener diode
    • Replies: 31
    • Forum: Pioneer Audio
  7. R

    Question about a power supply cap..

    I'm working on VCR that I bought as-is, will not power on. I pulled the power supply out and started checking things out. No fuses are blown. Right away, I found a 47 μF / 63V cap that showed as a dead short on my meter. There is a 10 Ohm fusible resistor upstream that is open. I pulled them...
  8. tusntuk2

    Can you replace 2sc1318 with Ksc2383 here? Sherwood S-7100A

    Wish I understood this better... how transistor application changes with the type of circuit and how it is used in this power supply and main amp. Problem: Replacing the C1318 in different circuits, (with what I have on hand). Can you can use a KSC2383 in the power supply of the Sherwood...
    • tusntuk2
    • Thread
    • c1318 ksc2383 ksc2690 power supply replace transistor s-7100a sherwood transistor application
    • Replies: 7
    • Forum: Solid State
  9. Yamaha5000

    Yamaha CA-1000/CA1000II Power Supply and Protection Circuit Diagnostics, & Lower SNR values with the QA403

    With the DVM + lead on the Base of TR708 and the - lead on E: On the V scale I read 15.32vdc and the relay is off On the mv scale the relay coil becomes active I can use the V and mv scale selector to act like a switch to turn the relay on and off. FYI the Emitter to E measures 15.84vdc...
    • Yamaha5000
    • Thread
    • 60 cycle hum crosstalk internal hookup wire power supply power supply caps protection circuit qa403 snr yahama amplifier yamaha ca-1000
    • Replies: 358
    • Forum: Yamaha
  10. tusntuk2

    SX-727 blown fuse - please help identify parts

    Merry Christmas AK'ers! I could use a little help solving a blown fuse problem on a SX-727. This unit was my first recap project, done 4 years ago. Following AK threads I bravely dug into a SX-727 to recap it, but little did I know how hard/easy it was! I figured even if it blew up it could...
    • tusntuk2
    • Thread
    • awm-027-d blown fuse diode help identify internal fuse power supply protection circuit recap sx-727
    • Replies: 2
    • Forum: Pioneer Audio
  11. Willarado

    Marantz 2238b power supply adjustment

    I am just finishing up restoring a Marantz 2238b and attempting to set the power supply voltage. I can only get it to 29 volts instead of the 35v stated in the manual. Bias and DC offset are spot on. Does anyone have suggestions? And it is a concern given that it is working and sounds fantastic?
    • Willarado
    • Thread
    • marantz marantz2238b power supply receiever
    • Replies: 13
    • Forum: Solid State
  12. mrz80

    After some years, back to trying to fix the MAC-4100 again

    Well hello again everyone. Almost five years ago (to judge from the date on the last post) I set my dead MAC-4100 aside in frustration and put the MX-112 and MC-275 into the main system (after determining that the 275's only problem was a tube that had cracked glass letting go). Here's the...
  13. H

    Yamaha A-1 amplifier thump on power off.

    Hi, I have a Yamaha A-1 that I’ve been working on and is now sounding great and has stable readings for Drive Circuit DC Offset, Idling Current, Power Supply voltage as per the manual. But, powering off just now by pressing the power button on the amp led to a substantial thump through the...
    • Hifibythekg
    • Thread
    • a-1 power supply thump thump in speaker yahama amplifier
    • Replies: 89
    • Forum: Yamaha
  14. KD2KGA

    Power & Fuses

    Quick story with advice and then a question at the end. I have a Pioneer SA-8800 that I had recapped by a tech years ago. Now I'm getting into doing things for myself and recently recapped a Technics SA-200 that I found. And look, I'm still alive. I had some power issues a few months back with...
  15. tcdriver

    Power Supply Model C-4PS01 For Use with a McIntosh C-4 Preamp

    McIntosh C-4 Power Supply Design Idea This post presents a Design Idea for an inexpensive power supply to power a McIntosh C-4 Audio Compensator. Early versions of this preamplifier used 6.3VAC to power the filaments. Later versions used an internal voltage doubler to provide a nominal 12VDC...
    • tcdriver
    • Thread
    • c-4 c-4ps01 mcintosh mcintosh c-8 mono power supply preamp tube
    • Replies: 5
    • Forum: McIntosh Audio
  16. Leestereo

    Why does Leestereo insist on increasing power supply/decoupling capacitors?

    I often get asked why should one consider judicious increases to the capacity of a power supply. I typically respond as such: It can be argued that the power supply is in the signal path, it's essentially in series with the output stage and hence does impact the sound of an amplifier. Nelson...
  17. Tangerine

    Converting input voltage from 100/110/120v to 240v

    Hello, I’m wondering if it’s conceivable to alter the power supply of a piece of gear to enable a different input voltage to that originally designed? Has anyone done such a thing? Are there “mod kits” or instructions out there that would enable such a change to be done? All discussions...
  18. goldswimmerb

    Sx-1280 power supply issues

    Working on an SX-1280 and I am suspicious I may have an issue in my PS, both my + and - 33v rails are about +-36v, everything seems to work except the DC offset is slow to settle (around 100mv and falling when the relay closes), max volume on phono causes a pop that causes the relay to close...
  19. ocdecio

    2238 Power Supply

    As per the Service Manual, I should be getting 46V at the collector of Q803. However I am getting 47.6V which I believe is responsible for the regulator becoming too hot (around 160F). The voltage before R801 is 50V. I am pondering if I should up the R801 resistor a bit to get it to the 46V...
  20. D

    Harman Kardon A-30K (A-300) power supply

    Hi! I just picked up a Harman Kardon A-30K, the kit version of the A-300. It works but someone replaced the power transformer from a 110V primary to a 250V but in doing so he also replaced the doubler circuit with a classic half wave rectifier fed from a 250-0-250v secondary winding. Only...
    • depaj
    • Thread
    • a-300 a-30k harman kardon power supply power transformer
    • Replies: 62
    • Forum: Tube Audio
  21. baconbadge

    Combining Filter Caps?

    Greetings, I have a Fisher 500c here where the previous owner combined the three sections of the C92 (50uf, 50uf, 50uf) filter can cap into a single 150uf cap. First pic is schematic, second pic is how it’s rewired: The numbers are the same, but does this configuration have any real-world...
    • baconbadge
    • Thread
    • filter capacitors fisher power supply ripple
    • Replies: 17
    • Forum: DIY
  22. I

    Philips GA 212 Power Supply Problems -- voltage too high

    So I've been working on this Philips 212 recently. I picked it up and it seemed to work OK as is powered up and I could select between 33 and 45, etc. I didn't think much of it. There were two axial electrolytic caps that I decided to replace. Upon removing the PCB one of the trim pots simply...
  23. cicada_17

    230V Avid Volvere turntable for U.S. use with 110V power supply?

    Hi, first post, am in need of advice regarding an overseas turntable. I have the opportunity to bring back a U.K. spec Avid Volvere turntable. My question is, can I simply purchase an Avid power supply that takes 110V/60hz U.S. voltage to power the turntable motor? Or would the motor be wired...
    • cicada_17
    • Thread
    • motor power supply turntable voltage
    • Replies: 3
    • Forum: Turntables
  24. James Cox

    Citation II help!

    Alright guys so I'm pretty bummed out here. I have a citation II that I picked up about 6 months ago that had been restored to stock values and worked perfectly aside from a little more background noise than I expected. I decided since I had pretty good luck restoring a few tube amps and...
    • James Cox
    • Thread
    • citation ii dead channel power supply repair tube amp
    • Replies: 4
    • Forum: Tube Audio
  25. mrk229

    EICO HF-89 Power Supply Modifications?

    Greetings. As noted in many places the EICO power supplies were mostly built to a just adequate specification. I am currently rebuilding an HF-89 and want to upgrade the power supply. Looking at various threads here at AK and other places has given me some ideas and they are presented in the...
    • mrk229
    • Thread
    • eico hf-89 power supply tube
    • Replies: 10
    • Forum: Tube Audio
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