Hot Rod Deluxe Pickle

Discussion in 'Amp Central Station' started by SmashMagnum, Nov 12, 2016.

  1. SmashMagnum

    SmashMagnum TDPRI Member

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    A friend of mine inherited a HRD last year, it supposedly worked “ok” for awhile. Recently it started buzzing and later going “full chaos mode”. I told him I would take a look at it, and when brought it home I found that he wasn't far off. The amp ran ungodly loud with no noticeable volume control whatsoever, also buzzing and popping. Moreover, I noticed one of the tubes was running super hot. I've never owned or peered inside a HRD before, but it definitely didn't appear normal.


    I'm not an Amp technician by any means, but I have tinkered with my own amps and guitars as well as my friends with success before. After breaking into it, and draining the caps, I found a few bad caps and resistors. Using a multimeter, I checked the volume pots, but did not appear to be any problems. I decided to replace them anyway, and ordered the Fromel supreme mod kit for it. After installing the kit I ran it for a test run, and was relieved to hear no buzzing or popping. However, I still don't seem have volume control. I do have master volume control, but have to keep it at like one and a half before it gets super loud. I went through and checked components that I believed to be part of that circuit, and did not find an issues. The one tube still seems to be running excessively hot as well. Basically come to the point that I believe i'm lost, and would appreciate some input, or suggestions.


    Thanks,
     
  2. SmashMagnum

    SmashMagnum TDPRI Member

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    20160824_215754.jpg
     
  3. SmashMagnum

    SmashMagnum TDPRI Member

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  4. wabashslim

    wabashslim Friend of Leo's

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    Looking at a schematic I see R5 & C1 near your burnt spot set the cathode voltage for V1A, your first preamp tube. There should be about 1.7v on p.3 of that one. If C1 is shorted or R5's value is way off (s/b 1.5k) that's bad. Also does your Drive switch and control work? What happens if you turn the Drive pot while the Drive switch is off?
    I'd change that V1 tube for sure but I don't think the volume issue is related. Can't tell from the picture but is V1 the hot one? Whatever it is, change it very soon.

    Did this amp ever get a beer bath?
     
  5. Wally

    Wally Telefied Ad Free Member

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    That clean mode volume is bypassed when in the drive mode. If the gain and MV are functioning all of the time and that first volume pot is not functioning at all, the amp is in drive mode at all times.
     
  6. Platefire

    Platefire Friend of Leo's

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    That tube glow appears to me to be a 6L6 red plating. If that is the case, you shouldn't be running the amp in that condition. It could take out other stuff in the amp like a transformer. Could be one of several things: Bad tube(switch power tubes to see if red glow follows the tube location or the socket location) if it follows the tube, it's the tube, if it stays with the socket it is circuit related, also could be bias voltage circuit is messed up or either set too high, or a bad coupling cap prior to the 6L6 letting DC voltage into the grid. The coupling cap purpose is to block DC voltage and let AC voltage pass----if it is bad and lets DC voltage pass it can cause that condition. You can check for cap leakage with a multi meter with the power tubes removed to prevent damage. If DC voltage is reaching the tube side of cap, the cap is bad.

    Don't know about the volume issue. I know if you plug a preamp/processor into the power amp in jack, it bypasses the amp Channel 1 and 2 preamp volume and uses the proscessor volume. If that switch in the power amp input jack stuck, it could cut the preamp volumes off. You might try spraying Deoxit cleaner in the jacks and plug a 1/4 plug into it multiple times to work the cleaner on the jack contacts to see if that helps. Platefire
     
    Last edited: Nov 13, 2016
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  7. Pup Tentacle

    Pup Tentacle Tele-Holic

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    if the channel switching is not working check the two large 5 watt resistors R-85 and R-86, they tend to burn up in these amps
     
  8. Wally

    Wally Telefied Ad Free Member

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    +1 on that redplating. This amp has problems...multiple problems. It may be tech time.
     
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  9. wabashslim

    wabashslim Friend of Leo's

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    "A man's got to understand his limitations". I would agree its probably tech time. Multiple, possibly cascading problems; you're an admitted tinkerer, not a tech; and it's not your amp. Worse yet, it's a Hot Rod Deluxe, a terribly over-engineered amp for all it does (I didn't care for the one I briefly had). Unless you find something obvious, and soon, better tell your friend to get his wallet ready for a draining.
     
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  10. Platefire

    Platefire Friend of Leo's

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    I owned one of the original HRD made in 1996 in the USA. It had a 50th Anniversery plate on the back from the time Leo built his first amp--1946.

    I had it for about 10 years and it never gave me an ounce of trouble.
    I never warmed up to the drive channel, more drive switch but the clean channel was pretty nice. Especially when you could use it at 5 or 6 on clean volume.

    Working on those PCB boards is not for the faint hearted. I have done it several times but never comfortable with it. Give me an old vintage point to point and I'm right at home. So you should know your capabilities and proceed based on that. Platefire
     
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  11. clintj

    clintj Friend of Leo's

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    Another vote for tech time. Somebody needs to sit down and catalog all the issues one at a time, and systematically verify the circuit is working properly. The nice thing with those is Fender listed all the expected AC and DC voltages right on the schematic for us.

    That redplating tube and the hum you described kind of creeps me out. That's a big "help me" sign that poor amp is waving at you.
     
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