Looking for a repair person

I'm still having trouble with the balance control on my Dynaco preamp. Thought it was was fixed locally but problem has resurfaced. I've decided to have the pot eliminated from the signal path. Looking for somebody within say 2 hours of zip 17701(central PA) that could do this while I wait. I have schematics/owners manual. I really don't want to ship this.
Yep, my name really is Bob.
Parasound HCA1500(indoor sound) and HCA1000(outdoor sound), Dynaco PAS4, Denon DP1200 w/Shure V15 Type V and Jico SAS stylus, Oppo BDP93, Marantz UD7007, modded Polk SDA 2B.

Comments

  • mhardy6647mhardy6647 Posts: 25,814
    edited July 27
    What's it, like a PAS-3 or a PAT-5 or?
    You ought to take a road trip up to northern NH and we can bypass the balance control together! Socially distanced & with face masks, but, you know...

    :)


    EDIT: Just outta curiosity -- you are sure that the control itself is the issue and that it is not a symptom of some other problem? Just checking.

  • VR3VR3 Posts: 23,914
    WILLIAM THALMANN

    MUSIC TECHNOLOGY, INC.

    5418 Port Royal Road

    Springfield, VA 22151

    703-764-7005 x106

    [email protected]

    www.musictechnology.com

    HOURS: 11AM-6PM Mon-Fri
    - Not Tom

    "No, that's silly talk. Dude, you can't possibly be this audio dumb so quit the act." - Doro
  • muncybobmuncybob Posts: 2,347
    It's a PAS4. Much better(so I'm told) than the previous Dynaco preamps. When it's right, it's RIGHT. I had it when the much more expensive Rhumba was making the rounds. I would say it was at least on par with it with a very good sounding phono stage to boot.

    I would love to see NH again(was brought up in Portsmouth) but traveling that far is not in the cards at this time.
    Yep, my name really is Bob.
    Parasound HCA1500(indoor sound) and HCA1000(outdoor sound), Dynaco PAS4, Denon DP1200 w/Shure V15 Type V and Jico SAS stylus, Oppo BDP93, Marantz UD7007, modded Polk SDA 2B.
  • muncybobmuncybob Posts: 2,347
    Port Royal is also too far but if I need to I can always ship it I guess.
    Yep, my name really is Bob.
    Parasound HCA1500(indoor sound) and HCA1000(outdoor sound), Dynaco PAS4, Denon DP1200 w/Shure V15 Type V and Jico SAS stylus, Oppo BDP93, Marantz UD7007, modded Polk SDA 2B.
  • mhardy6647mhardy6647 Posts: 25,814
    muncybob wrote: »
    Port Royal is also too far but if I need to I can always ship it I guess.

    The address was Springfield (FWIW) -- I am a little rusty on my VA geography ('cept the places our son's lived, and currently lives), so I don't know if that's better or not.


    So, what does the balance do? Is the pot scratchy, or does it just cut out, or something else?

  • muncybobmuncybob Posts: 2,347
    Yea, misread that.

    Right channel will cut out. If you put pressure on the balance knob vertically you usually can get it back but it may not stay. The pots on this unit are sealed, no way to clean. I don't think it's a corrosion problem. At first I suspected something on the board since pushing the knob up/down helped but the board checks out OK.

    Both my power amps have pots for each channel so I really don't need this one on the PAS, just want it eliminated. There are a lot of things I'll try my hand at but this ain't one of them.
    Yep, my name really is Bob.
    Parasound HCA1500(indoor sound) and HCA1000(outdoor sound), Dynaco PAS4, Denon DP1200 w/Shure V15 Type V and Jico SAS stylus, Oppo BDP93, Marantz UD7007, modded Polk SDA 2B.
  • mhardy6647mhardy6647 Posts: 25,814
    heh -- "no way to clean".
    That, ol' son is a challenge. B)

    DeOxit is really mobile stuff. Squirtin' a little "in, with and under" most controls will result in a little finagling its way in ;)

    There are also worst case scenario tactics to unseal such recalcitrant pots.

    Do you have the schematic? bet "we" could find a pot to replace it without too much difficulty.

    Again -- just sayin'.

  • ClipdatClipdat Posts: 8,309
    Bob: It's a sealed pot, it can't be fixed.

    Mark: Don't threaten me with a good time!
  • mhardy6647mhardy6647 Posts: 25,814
    Clipdat wrote: »
    Bob: It's a sealed pot, it can't be fixed.

    Mark: Don't threaten me with a good time!

    Exactly!
    Man*. The tool-using animal.


    ___________
    * I mean "Man" as in H. sapiens sapiens, not "man" as in "23XY genotype" -- in case that's not abundantly clear. :|

  • muncybobmuncybob Posts: 2,347
    Yep, my name really is Bob.
    Parasound HCA1500(indoor sound) and HCA1000(outdoor sound), Dynaco PAS4, Denon DP1200 w/Shure V15 Type V and Jico SAS stylus, Oppo BDP93, Marantz UD7007, modded Polk SDA 2B.
  • mhardy6647mhardy6647 Posts: 25,814
    cool -- I'll be gettin' back to you anon on this.
    thanks!
  • mhardy6647mhardy6647 Posts: 25,814
    edited July 28
    It is a sealed pot (looks like one of those Alps pots) all righty -- and a little more complicated than I was expecting, too :blush:

    oss9nae3c1t9.png
    https://therobbcollections.blogspot.com/2018/06/dynaco-given-second-life-pan-orient.html

    3ih5kqkdkfq1.png

    EDIT: I am an idiot :p
    But, yeah, it can be jumpered out fo' sho.
  • muncybobmuncybob Posts: 2,347
    I found a shop that specializes in older equipment. He said in order to eliminate the pot there would need to be a number of resistors installed and suggested trying to replace the pot instead. I may be making a road trip(1.5 hours) to see him Saturday morning. The last thing he said bumms me out though, they are currently swamped :(
    Yep, my name really is Bob.
    Parasound HCA1500(indoor sound) and HCA1000(outdoor sound), Dynaco PAS4, Denon DP1200 w/Shure V15 Type V and Jico SAS stylus, Oppo BDP93, Marantz UD7007, modded Polk SDA 2B.
  • muncybobmuncybob Posts: 2,347
    BTW, thanks for the link!
    Yep, my name really is Bob.
    Parasound HCA1500(indoor sound) and HCA1000(outdoor sound), Dynaco PAS4, Denon DP1200 w/Shure V15 Type V and Jico SAS stylus, Oppo BDP93, Marantz UD7007, modded Polk SDA 2B.
  • muncybobmuncybob Posts: 2,347
    Dropping off the pre Saturday morning. In speaking with the shop owner I think I've found the right person. He just rebuilt a ST70(he said once done it was one of the better tube amps he's ever heard) and is somewhat familiar with Dynaco although not sure if he ever worked on a PAS4. When I explained the pot is sealed and can't be cleaned he said would try a hypodermic needle with Deoxit and then somehow gets compressed air into the pot as the 1st step. I still think it's something on the board....time will tell.
    Yep, my name really is Bob.
    Parasound HCA1500(indoor sound) and HCA1000(outdoor sound), Dynaco PAS4, Denon DP1200 w/Shure V15 Type V and Jico SAS stylus, Oppo BDP93, Marantz UD7007, modded Polk SDA 2B.
  • mhardy6647mhardy6647 Posts: 25,814
    muncybob wrote: »
    ... When I explained the pot is sealed and can't be cleaned he said would try a hypodermic needle with Deoxit and then somehow gets compressed air into the pot as the 1st step.
    heh-heh-heh... ;)
    I still think it's something on the board....time will tell.

    I've gotta say, when I saw the picture of the innards of a PAS-4, I was not encouraged to see the whole shootin' match on a single big PC board. A few decades on, that's not going to improve reliability. There may well be damaged traces from the board flexing over the years. Not irreparable, but a pain to mitigate.

    We'll hope for the best.
  • dcmeigsdcmeigs Posts: 698
    edited July 31
    I’ve used DeOxIt on sealed pots with good success. Get a drill bit the same size as the plastic straw and drill a small hole in the top of the enclosure over to the side. Not in the center! Drill slowly and wipe away the plastic as you go so you don’t deposit any in the pot. Spray, rotate the pot about 2 dozen times and Bobs Your Uncle. Cover the hole with blue tape and swear it never happened.
    The world is full of answers, some are right and some are wrong. - Neil Young
  • mhardy6647mhardy6647 Posts: 25,814
    dcmeigs wrote: »
    I’ve used DeOxIt on sealed pots with good success. Get a drill bit the same size as the plastic straw and drill a small hole in the top of the enclosure over to the side. Not in the center! Drill slowly and wipe away the plastic as you go so you don’t deposit any in the pot. Spray, rotate the pot about 2 dozen times and Bobs Your Uncle. Cover the hole with blue tape and swear it never happened.

    I stopped short of invoking the drill bit gambit earlier in this thread -- didn't want to freak the young lad out, you know?

    :|
  • BlueFoxBlueFox Posts: 13,535
    Just spray it on the shaft going into it.
    Bud - Silicon Valley

    Lumin X1 file player
    Sony XA-5400ES SACD
    Pass XP-22 pre, X600.5 amps
    Magico S5 MKII Mcast Rose speakers, SPOD spikes

    Shunyata Triton v3/Typhon QR on preamp, Denali 2000 (2) on amps
    Shunyata Sigma XLR analog ICs, Sigma speaker cables
    Shunyata Sigma HC (2), Sigma Analog, Sigma Digital, Z Anaconda (3) power cables

    Mapleshade Samson V.3 four shelf solid maple rack, Micropoint brass footers
    Three 20 amp circuits.
  • mhardy6647mhardy6647 Posts: 25,814
    edited August 1
    BlueFox wrote: »
    Just spray it on the shaft going into it.

    That's plan A.
    Plan B involves tools. :)

    0aavyji7ux1t.png

    tenor.gif?itemid=16749349

  • muncybobmuncybob Posts: 2,347
    Well, I dropped it of yesterday and I'm feeling good this time about who is doing the work for me. This guy is proud of his work, showed me several photos on circuits/board he's recently worked on. I drooled over the Teac reel to reel on his shelf. He works on just about anything and loves his high end customers but also realizes I ain't one of them. His friend stopped in and advised me the the wait will be well worth it. He plans to fix the problem and go over things in detail. Also told me he has 40+ years experience w/stereo equipment and loves working on vintage gear. Now the waiting game begins..........
    Yep, my name really is Bob.
    Parasound HCA1500(indoor sound) and HCA1000(outdoor sound), Dynaco PAS4, Denon DP1200 w/Shure V15 Type V and Jico SAS stylus, Oppo BDP93, Marantz UD7007, modded Polk SDA 2B.
  • mhardy6647mhardy6647 Posts: 25,814
    He's gettin' the hammer drill warmed up even now...


    ;)

  • dcmeigsdcmeigs Posts: 698
    mhardy6647 wrote: »
    dcmeigs wrote: »
    I’ve used DeOxIt on sealed pots with good success. Get a drill bit the same size as the plastic straw and drill a small hole in the top of the enclosure over to the side. Not in the center! Drill slowly and wipe away the plastic as you go so you don’t deposit any in the pot. Spray, rotate the pot about 2 dozen times and Bobs Your Uncle. Cover the hole with blue tape and swear it never happened.

    I stopped short of invoking the drill bit gambit earlier in this thread -- didn't want to freak the young lad out, you know?

    :|


    As you seem to know, that technique works well on the cubic pots like the ALPS. I’m not sure there is a corner in those pots in the photo. Can you identify those?
    The world is full of answers, some are right and some are wrong. - Neil Young
  • mhardy6647mhardy6647 Posts: 25,814
    dcmeigs wrote: »
    mhardy6647 wrote: »
    dcmeigs wrote: »
    I’ve used DeOxIt on sealed pots with good success. Get a drill bit the same size as the plastic straw and drill a small hole in the top of the enclosure over to the side. Not in the center! Drill slowly and wipe away the plastic as you go so you don’t deposit any in the pot. Spray, rotate the pot about 2 dozen times and Bobs Your Uncle. Cover the hole with blue tape and swear it never happened.

    I stopped short of invoking the drill bit gambit earlier in this thread -- didn't want to freak the young lad out, you know?

    :|


    As you seem to know, that technique works well on the cubic pots like the ALPS. I’m not sure there is a corner in those pots in the photo. Can you identify those?

    I thought they looked like (or at least similar to) ALPS pots to me(?).


    2gpkcdj2f8vj.png
    ou1gxl1dnawa.png
    3dgltki6p1zc.png

    Nice to see a post from you! Hope all is well.

    PS I don't think that replacing the pot with a set of fixed resistors would be too awful, either, since it's on a PCB (assuming it's a reasonably sturdy PCB to withstand desoldering without traces lifting). Of course, adjustability would be lost via that route.
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