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  1. tbone8

    Pioneer SX-9000 signal meter issue

    Got this old gal up and running but with one issue, the signal meter. The pointer is stuck all the way to the right and I assume it sweeps from left to right? If I tap it hard enough, it will move about 1/8" to the left and stay there, then tapping sets it back all the way to the right. I put a...
  2. tbone8

    Pioneer SX-9000 main amp pot replacement

    Picked up one of these bad boys the other day, was told it kept blowing fuses. All four adjustment pots were buggered. Decided to mount the replacements on the bottom of the board for easier adjustment as others on the interweb has suggested. No pics that I could find were posted so thought I...
  3. tbone8

    Marantz 6370Q, need some cartridge recommendations

    I have two Marantz 6370Q turntables been collecting dust for a few years now and decided to get one up and going. One came with a Shure Me95ED with some sort of aftermarket stylus that really doesn't fit the cartridge. The other came with a Stanton 681EEE cartridge with a trashed stylus. The...
  4. tbone8

    Marantz SD9000 flakey play speed finally solved!

    For literally two years, I have messed off and on trying to figger out why this deck would not play at a reliable steady speed. I tore the motor apart twice, most recently today to replace the three transistors in it and a tantalum cap. Put it back together and ran good for a while and...
  5. tbone8

    Marantz balance slider repair

    Thought I would post this fix. I cut a thin strip of 16 gauge steel and traced the pattern from another slider I had. I used my bench grinder to shape the end then a dremmel with a cutting disc for fine refinement. The 16 gauge steel is slightly thicker than the original piece so used a hand...
  6. tbone8

    Kenwood KR-77 missing slug in IF can???

    Working on an old KR-77, got it recapped, replaced a bad op-amp and ready to do the alignment. So, supposed to adjust upper and lower slugs of L2, 3 and 5 for the FM IF except L5 only has a slug near the bottom. Its a tall can like the other two with 2 slugs. It does tune FM ok but seems to need...
  7. tbone8

    FM discriminator transformer toast

    Been screwing with an old Marantz 27 receiver I have had since I was a kid, in fact, my first piece of audio gear. My aunt gave it to me some 40 years ago and the FM was never right with it. Fast forward to today, after a bunch of other fixes, got to the discriminator alignment and one core...
  8. tbone8

    3 Mica pads Pioneer SX-850?

    Re-habbing the power amp, all the transistors are toast on one channel. When removing the outputs, each one has 3 pads per transistor? I don't think this has ever been apart, can this be right?
  9. tbone8

    Marantz model 27 IF alignments

    Getting around to fiddeling with my old model 27 that I got from a relative when I was a teenager some 40 years ago. Have done a couple IF alignments on Marantz stuff and wanted to double check this one. As usual, the manual go by kinda vague on exact points, it states: The other Marantz...
  10. tbone8

    Zener diode amp circuit protection modification

    As part of my journey in electronics, this has been a good learning exercise for me. There is a protection mod for this old amp I am fiddling with. It explains the mod but no values for the diodes. I want to figger out what will work here. I assume the over voltage protection for the zeners...
  11. tbone8

    Very interesting, lots of pics, weak transistor

    Picked up an old GE 5286A a couple months ago. Sounded horrible and right channel weaker than the left. Cleaned all the pots and switches, still lots of static. Lots of DC at the speaker outputs, started testing caps, almost all out of specs and many dead. Recapped the whole thing, sounds much...
  12. tbone8

    Holy bad caps Batman!

    Picked up an old Panasonic boombox. Relatively good shape and relatively clean. Fired it up, lots of static and sounded like el crapola. Started by cleaning the pots and switches, they were dirty inside. Better but still sounded awful. All kinds of DC at the speakers, couldn't even adjust the...
  13. tbone8

    Marantz IC question

    This old PM700 has a LED meter that is faulty. After going through the driver board for it, figgered out an IC chip is bad. Had a channel blown when I got it and it musta sent some bad juju to the IC. Anyways, it's old, not particularly valuable but would like to fix it. The chip is a Sharp...
  14. tbone8

    Am I missing something, kµV?

    Tuning meter on my 2252B out of the blue got out of alignment. Adjusted the lower core on the discriminator transformer and all is good now. As long as I am in there, thought I would adjust the upper core with the distortion analyzer. The manual says, "to set the signal generator to 1kµV at 98...
  15. tbone8

    Found a fantastic source on learning electronics

    Picked up a 1966 edition of the National Radio Institute Home Study Course. Must be over a hundred booklets grouped in separate binders. I probably have 10 or so electronics books but these, in my opinion, are the best. Electrical theory as it pertains to radio and TV primarily, is explained so...
  16. tbone8

    Picked up a neat Teac amp

    Picked up a Teac A-H500 integrated amp the other day. Has a big toroidal transformer inside, sounds unbelievably good. Real good shape, looks like had a couple small electrolytics were replaced at one time. No hiss's or hums, just adjusted the bias and gonna use it and an ipod player in the...
  17. tbone8

    Need a little help with an old amp

    I have this Marantz PM700 I essentially got for free a few years ago. One channel was hosed on it, put new output and driver transistors in it. R766 &Q726 was shorted out and Q806 on the power board was dead. I recapped the power board, amps and tone boards. I have desoldered and checked darn...
  18. tbone8

    Those darn 90° board connectors

    Finally got my 1180DC back together. After replacing lots of crispy resistors and fried transistors, it shows signs of life. Fired it up with the dim bulb tester, no excessive power draw, good sign. Figured the first thing to do was check the DC offset, very jumpy on the side that didn't burn...
  19. tbone8

    Protection relay half price

    When I ordered the relay for this 1180DC, I accidentally ordered a MY4-DC24(S) instead of a MY4-02 DC24. The one I got cost $6.63 and the other is $11.41 at Mouser. Turns out, they are both the same except for the extra pins which the board has holes for and the mount. . A little dremmel...
  20. tbone8

    1180 DC protection board

    Steadily progressing on this amp, got the main P700 board almost done, waiting on a couple parts. So, moved on to the PN00 board, replaced all the electrolytics, man, the old ones look like they really got cooked. I have been testing all the transistors and diodes on the board, have a couple...
  21. tbone8

    Push button cross over models

    I am beginning to thing this 1180DC is cursed! Never the less, one of the pushbutton switches is busted, common, fixed quite a few. Pull out one of my spare switch boards to size a new shaft when I notice the 11880DC is a tad different. First, the little shaft retaining clip is secured by some...
  22. tbone8

    All aluminum volume knob really stuck

    Decided to take the front panel off the 1180DC I am working on. Got to the last knob, the volume and loosened the set screws and that thing will not come off with spoons. Since it has set screws, is it a round shaft then? I am guessing the aluminum has reacted with the shaft and galvanically...
  23. tbone8

    Did the 1180DC power board today

    Finally started working on this amp I posted about a couple weeks ago. Started with the power board, used Nichicon PW caps and replaced the voltage regulators too. Gonna move on to the amp boards next, 3 of 4 output transistors on one channel were shorted, lots of barbecued parts to replace...
  24. tbone8

    Rut Ro

    Norway on Wednesday completed its transition to digital radio, becoming the first country in the world to shut down national broadcasts of its FM radio network despite some grumblings. As scheduled, the country's most northern regions and the Svalbard archipelago in the Arctic switched to...
  25. tbone8

    Dim bulb tester

    I had posted a question about an amp I am working on in the Marantz section and one of the wonderful posters (Catrafter) here gave me a great tip, a dim bulb tester. For the seasoned veterans, this is probably standard bench protocol but for a relative novice like myself, I thought this was a...
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