Page 2 of 2 FirstFirst 12
Results 36 to 60 of 60

Thread: Damn near started a fire in my Hot Rod Deluxe

  1. #36
    Lifetime Member Enzo's Avatar
    Join Date
    May 2006
    Location
    Lansing, Michigan, USA
    Posts
    33,497
    Thumbs Up/Down
    Received: 2,543/7
    Given: 0/0
    Rep Power
    57
    IC 1 & IC2 (T072) are both bad...
    I think you are right, but considering all the trouble the OP has had with his 15v rails, we need to verify that those ICs are indeed getting proper power at the corner pins.

    And when it comes down to troubleshooting the channel switching, PLEASE use the TP guide next to the switching circuit.

    0 Not allowed! Not allowed!
    Education is what you're left with after you have forgotten what you have learned.

  2. #37
    Member
    Join Date
    Jan 2020
    Posts
    38
    Thumbs Up/Down
    Received: 9/0
    Given: 0/0
    Rep Power
    0
    Thanks. I’m looking on Digikey for ICs. Lots of choices,I need to be careful to order the thru hole versions.

    I’m not up on the lingo -OP is Original Poster?

    Explain what the TP Guide is?

    1 Not allowed! Not allowed!

  3. #38
    Supporting Member The Dude's Avatar
    Join Date
    May 2010
    Location
    Sioux Falls, SD
    Posts
    6,934
    Thumbs Up/Down
    Received: 1,695/2
    Given: 1,220/1
    Rep Power
    18
    Yes, OP is Original Poster. TP is test point.

    0 Not allowed! Not allowed!
    ďYeah, well, you know, thatís just, like, your opinion, man.Ē

  4. #39
    Member
    Join Date
    Jan 2020
    Posts
    38
    Thumbs Up/Down
    Received: 9/0
    Given: 0/0
    Rep Power
    0
    Ok, yes I am using the TP guide that is companion to the schematic. I took several readings today and several are not reading what I would expect. I only had a few mins today but will post some later tonite or tomorrow.

    Thanks.

    0 Not allowed! Not allowed!

  5. #40
    Lifetime Member Enzo's Avatar
    Join Date
    May 2006
    Location
    Lansing, Michigan, USA
    Posts
    33,497
    Thumbs Up/Down
    Received: 2,543/7
    Given: 0/0
    Rep Power
    57
    The ICs in your Fender are what we call DIP - dual inline package - mostly plastic, though some are ceramic. Doesn't matter for you. Your ICs sit on the circuit board with their legs extending through the holes in the board, soldered on the other side. This is referred to as "through-hole" mounting to contrast "surface mount"..Surface mount or SM, are the tiny parts soldered right on top of the board.

    Other alphabets like SOIC are surface mounts. If it doesn't say DIP, it isn't going to fit. DIP ICs come in various number of legs, depending upon type. DIP-8 means same thing as plain old DIP if it is an 8 legged part.

    1 Not allowed! Not allowed!
    Education is what you're left with after you have forgotten what you have learned.

  6. #41
    Member
    Join Date
    Jan 2020
    Posts
    38
    Thumbs Up/Down
    Received: 9/0
    Given: 0/0
    Rep Power
    0
    Thanks for the explanation. TP testing tomorrow, may have to order some parts.

    0 Not allowed! Not allowed!

  7. #42
    Member
    Join Date
    Jan 2020
    Posts
    38
    Thumbs Up/Down
    Received: 9/0
    Given: 0/0
    Rep Power
    0
    Did TP testing and the results are more than confusing. Almost nothing reads in spec. (And I put a new battery in my old DMM)

    Test point

    TP Read Expected Read

    2 0 100mv
    3 1.82 1.72v
    4 -1.9 13mv
    5 Wandered 252mv
    6 1.72 1.72
    7 .3 .33
    8 220v 850mv
    9 1.92 1.72v
    10 .5 500mv
    11 223v 13.3V
    12 1.87v 1.72v
    13 10.74 1.2v
    14 15.4 66mv
    15 15.7 66mv
    16 39 39vac
    17 35.3 1.2vac
    18 2.2 1.14vac
    19 0 870mv
    20 -18.65 11.6v
    21 -18-65
    22 13.56
    23 -.33 744mv


    24-30 or so were inaccessible due to mounting on the daughter board housing the tubes. Still mounted in the chassis.

    Testing was done following the procedure on the schematic. Pots at 1/2, reverb off (CCV) etc.

    I have ordered replacement ICs for all three. Of note, components R4, r3, R11, R16, R22 all make an audible pop and or scratch when probed.

    TP 19 Tp20 and Tp 21 - 0, 18.68 and 18.65 are pins 1,3,7.


    Tp 32 -.49
    Tp33 -.49
    Tp34 -14.8
    Tp35 .5
    TP36 1.0

    U2 pins 2,3, 5,6,7.

    Anyone? Thanks very much.

    0 Not allowed! Not allowed!
    Last edited by Oldmactech; 03-11-2020 at 09:46 PM.

  8. #43
    Don't forget the joker g1's Avatar
    Join Date
    Feb 2010
    Location
    Canada, somewhere north of Fargo
    Posts
    12,654
    Thumbs Up/Down
    Received: 2,189/24
    Given: 5,521/11
    Rep Power
    24
    Quote Originally Posted by Enzo View Post
    And when it comes down to troubleshooting the channel switching, PLEASE use the TP guide next to the switching circuit.
    Quote Originally Posted by Oldmactech View Post
    Ok, yes I am using the TP guide that is companion to the schematic. I took several readings today and several are not reading what I would expect.
    I think you misunderstood Enzo and are referring to the TP layout drawing.

    On the schematic itself, in the lower left area, there are notes on what voltage you should see on TP's 31-36 under various switch conditions. Those are the ones you need to check for now. Some you can't do without the footswitch, but most you can.

    0 Not allowed! Not allowed!
    "Everything is better with a tube. I have a customer with an all-tube pacemaker. His heartbeat is steady, reassuring and dependable, not like a modern heartbeat. And if it goes wrong he can fix it himself. You can't do that with SMD." - Mick Bailey

  9. #44
    Supporting Member nevetslab's Avatar
    Join Date
    Apr 2010
    Location
    Burbank, CA
    Posts
    2,110
    Thumbs Up/Down
    Received: 787/1
    Given: 1,925/1
    Rep Power
    13
    We were just dealing with you getting your +/- 16V Power Supply stable, then dealing with your Channel Switching NOT working. There is a chart on the left side of the schematic under the heading "Footswitch Operation", which gives you TP31 thru TP36 with specific Footswitch or panel switch settings. That's for sorting out the problems with the Channel Switching operation, which isn't yet working.

    You had already measured the voltages on U1, U2 & U3. U1 & U2 were latched up, and need to be replaced. And what you had for U3 wasn't anywhere in the ballpark for TP33 (U3 Pin 7) & TP36 (U3 Pin 1). That IC also needs to be changed JRC 4560D. As your amp is, apart from the amp switching and the Reverb not working, functional, so I wouldn't waste time trying to wander thru all of the schematic's Test Points....that WILL drive you nuts, and, we're beyond that.

    0 Not allowed! Not allowed!
    Logic is an organized way of going wrong with confidence

  10. #45
    Member
    Join Date
    Jan 2020
    Posts
    38
    Thumbs Up/Down
    Received: 9/0
    Given: 0/0
    Rep Power
    0
    Thanks. Indeed, will drive one nuts. Interesting how Fender puts the test points upside down on the chart.

    Can’t do anything until the ICs get here, ought to be fun de-soldering all 8 points on them.

    0 Not allowed! Not allowed!

  11. #46
    Senior Member
    Join Date
    Jan 2011
    Location
    NorCal
    Posts
    488
    Thumbs Up/Down
    Received: 105/10
    Given: 120/0
    Rep Power
    10
    Quote Originally Posted by Oldmactech View Post
    ought to be fun de-soldering all 8 points on them.
    Clip the pins before desoldering. Makes it easy, with a basic soldering iron.

    2 Not allowed! Not allowed!
    --
    I build and repair guitar amps
    http://amps.monkeymatic.com

  12. #47
    Member
    Join Date
    Jan 2020
    Posts
    38
    Thumbs Up/Down
    Received: 9/0
    Given: 0/0
    Rep Power
    0
    Followup:

    Made some progress, replaced all 3 ICís, fired right up, both channels function, reverb back, all controls functioning. Sound is loud, maybe little funky. Extra drive button caused motor boating once then was normal? Maybe since I donít have the footswitch?

    One bit of concern-when I turn it off there was a fuzz tone like decay with hum. Typically when it goes of, just goes quiet. Iíll take some voltages later, re-inspect my IC soldering for sloppy.

    Thanks to all that gave me sound advice.

    3 Not allowed! Not allowed!

  13. #48
    Supporting Member nevetslab's Avatar
    Join Date
    Apr 2010
    Location
    Burbank, CA
    Posts
    2,110
    Thumbs Up/Down
    Received: 787/1
    Given: 1,925/1
    Rep Power
    13
    This is the first report I've heard about a Hot Rod Deluxe or Deville motorboating in the More Drive mode. Lack of foot switch wouldn't be cause. I'd have to go back to read your initial post(s) to see if you still have the original Illinois Filter Capacitors in the amp. They are known to go bad and cause issues, while I've never seen one motorboat.

    All of the Hot Rod series amps in our rental inventory at CenterStaging, LLC in Burbank have had the gain reduced a bit in the More Drive mode. It's a simple change. I've added 604 ohm resistors (560R or 620R also work) in series with the cathode caps C8 & C9, and changing V2 from 12AX7 to a 12AY7. Still yields plenty of additional gain in the More Drive mode, while no longer ripping your ears out.

    Click image for larger version. 

Name:	Fender HR Dlx, FR curves Cntrols @ 5-1 copy.jpg 
Views:	8 
Size:	1.24 MB 
ID:	57416 Click image for larger version. 

Name:	Fender HR Dlx, FR curves Cntrols @ 5-2 copy.jpg 
Views:	6 
Size:	1.27 MB 
ID:	57417

    2 Not allowed! Not allowed!
    Logic is an organized way of going wrong with confidence

  14. #49
    Member
    Join Date
    Jan 2020
    Posts
    38
    Thumbs Up/Down
    Received: 9/0
    Given: 0/0
    Rep Power
    0
    Thanks. The filter caps were swapped.

    This thing is stiill weird and unpredictable. Yellow drive switch lights before switching out of standby (with drive switch not engaged). After playing clean for 30 seconds or so the drive switch goes off acts normal switching to drive (yellow), more drive (red.) Once the more drive caused a loud bellow (best I can describe). The yellow drive light reacts to chopstick probe so it may just be loose but wouldnít be on with no switch would it?

    Clean channel sounds lousy. Almost wondering if the speaker is blown. Highs ok, low E, A awful. Tone controls all function, donít help much. Drive channel sounds ok.
    Take it apart I guess.

    0 Not allowed! Not allowed!

  15. #50
    Supporting Member nevetslab's Avatar
    Join Date
    Apr 2010
    Location
    Burbank, CA
    Posts
    2,110
    Thumbs Up/Down
    Received: 787/1
    Given: 1,925/1
    Rep Power
    13
    Quote Originally Posted by Oldmactech View Post
    Thanks. The filter caps were swapped.

    This thing is stiill weird and unpredictable. Yellow drive switch lights before switching out of standby (with drive switch not engaged). After playing clean for 30 seconds or so the drive switch goes off acts normal switching to drive (yellow), more drive (red.) Once the more drive caused a loud bellow (best I can describe). The yellow drive light reacts to chopstick probe so it may just be loose but wouldn’t be on with no switch would it?

    Clean channel sounds lousy. Almost wondering if the speaker is blown. Highs ok, low E, A awful. Tone controls all function, don’t help much. Drive channel sounds ok.
    Take it apart I guess.
    I'd be guessing you have more than one fractured solder joints on both the main PCB (which is a PITA to extract) and the Tube PCB. You'll need very bright light and magnification to see the radial fracture joints where the solder has separated from the component leads. I find the pot terminals, the input jacks, the Foot Switch Jack, the Preamp Out & Power Amp input jacks with these fractures, all the high current connections, which include the area you've already had to work on...the 5W zeners for the +/- 16V supply, those 470 ohm/5W dropping resistors, the bias pot, the filter caps associated with that +/- 16V supply, the main buss caps' connections. Fender has made variations in their PCB productions, where there's plenty of pad size for the filter caps, but the chose to only expose a tiny little circle in the middle and plate those, so very little solder pad is present to solder the cap leads. I've had to unsolder those cap leads, then scrape away teh solder mask and re-tin the pads, then fold the cap leads back down and solder them into place again to get proper solder joints. I spend a fair amount of time inspecting and repairing anything that looks shabby. AND, beware....the PCB quality on the Hot Rod Series is piss poor. Solder pads lift with the greatest of ease, so be patient and exacting. I've had broken traces separate from the component solder pad before on these amps, with behavior as you've described. Once all have been found, all the amps in our rental inventory behave well.

    And, those hard ribbon cables that tie the main PCB to the Tube PCB are known to break all too easily.

    As to your sound.....being able to patch signal directly into the Power Amp Section helps isolate where problems are occurring. I will always disconnect the speaker plug, and connect it to my Test Oscillator (which will drive speakers directly with warble-sine wave, much easier to listen to than pure sine, and often bust bad speakers, as well as speakers/baffles whose mtg hardware is totally loose and resonates like crazy. When all else is right, then I'll reconnect it to the amp, of course.

    0 Not allowed! Not allowed!
    Last edited by nevetslab; 03-19-2020 at 06:36 PM.
    Logic is an organized way of going wrong with confidence

  16. #51
    Member
    Join Date
    Jan 2020
    Posts
    38
    Thumbs Up/Down
    Received: 9/0
    Given: 0/0
    Rep Power
    0
    Thanks, I don’t have a signal generator.

    I did connect a known good external cabinet and it has the same distorted sound. Seems mostly the lower tones, lower open E, Open A etc. Sounds honky, dirty, fuzzy, brittle. Etc.

    0 Not allowed! Not allowed!

  17. #52
    Lifetime Member Enzo's Avatar
    Join Date
    May 2006
    Location
    Lansing, Michigan, USA
    Posts
    33,497
    Thumbs Up/Down
    Received: 2,543/7
    Given: 0/0
    Rep Power
    57
    I've added 604 ohm resistors

    OK, now exactly WHY would you (or anyone else for that matter) have 604 ohm resistors in stock? I can see maybe 1760 ohm resistors or even 221.4k, but 604?

    0 Not allowed! Not allowed!
    Education is what you're left with after you have forgotten what you have learned.

  18. #53
    Supporting Member nevetslab's Avatar
    Join Date
    Apr 2010
    Location
    Burbank, CA
    Posts
    2,110
    Thumbs Up/Down
    Received: 787/1
    Given: 1,925/1
    Rep Power
    13
    Quote Originally Posted by Enzo View Post
    OK, now exactly WHY would you (or anyone else for that matter) have 604 ohm resistors in stock? I can see maybe 1760 ohm resistors or even 221.4k, but 604?
    Prior to changing V2 to a 12AY7, when I was empirically adjusting the gain reduction on the two V2 cathode circuits, 600 ohms sounded closer than 560 ohms or 620 ohms. So, I had settled on 604 ohms. Doing that exercise with a 12AY7 in place, the difference was much less between those nearest values. butm, of course, either value will do...........it's just a guitar amp, after all.

    Click image for larger version. 

Name:	More Drive Mod-1.jpg 
Views:	12 
Size:	169.7 KB 
ID:	57480 Click image for larger version. 

Name:	More Drive Mod-2.jpg 
Views:	8 
Size:	161.4 KB 
ID:	57481

    0 Not allowed! Not allowed!
    Logic is an organized way of going wrong with confidence

  19. #54
    Lifetime Member Enzo's Avatar
    Join Date
    May 2006
    Location
    Lansing, Michigan, USA
    Posts
    33,497
    Thumbs Up/Down
    Received: 2,543/7
    Given: 0/0
    Rep Power
    57
    Of course I was just poking fun, but how is it you have 604 ohm resistors in stock? Is that a standard 1% value and I am just not aware?

    0 Not allowed! Not allowed!
    Education is what you're left with after you have forgotten what you have learned.

  20. #55
    Supporting Member nevetslab's Avatar
    Join Date
    Apr 2010
    Location
    Burbank, CA
    Posts
    2,110
    Thumbs Up/Down
    Received: 787/1
    Given: 1,925/1
    Rep Power
    13
    Quote Originally Posted by Enzo View Post
    Of course I was just poking fun, but how is it you have 604 ohm resistors in stock? Is that a standard 1% value and I am just not aware?
    After I settled on that 604 ohm value, I had ordered 50 pcs during a Mouser Parts Order, so I've had them on hand ever since. I think I re-ordered as I've put the mod into all of our rental Hot Rod Series, along with those at AuntieM over in Monrovia, nearby (near Pasadena)...another major backline gear & sound system rental facility.

    0 Not allowed! Not allowed!
    Logic is an organized way of going wrong with confidence

  21. #56
    Member
    Join Date
    Jan 2020
    Posts
    38
    Thumbs Up/Down
    Received: 9/0
    Given: 0/0
    Rep Power
    0
    Interesting-donít think Iíll try that.

    So, today I went over some solder joints on the tube daughter board and the sound quality seems to have improved a bit, no idea specifically why.

    Oddly the yellow drive light still cones on and stays on but only the clean channels makes sound until 15-20 seconds into playing the yellow light goes off and now both drive and clean channels function including yellow light and red ď more driveĒ light.
    Almost like it needs time to warm up. One of the ICís I replaced not making correct contact?
    I am not using a pedal switch but after the 15-20 second warmup there is an audible (not amplified) click from the PCB, until the initial period no click is heard.
    Thanks.

    0 Not allowed! Not allowed!

  22. #57
    Don't forget the joker g1's Avatar
    Join Date
    Feb 2010
    Location
    Canada, somewhere north of Fargo
    Posts
    12,654
    Thumbs Up/Down
    Received: 2,189/24
    Given: 5,521/11
    Rep Power
    24
    Monitor your +15V during warmup, then do same for -15V.
    Let it cool between, so you have the same delay before the click.

    0 Not allowed! Not allowed!
    "Everything is better with a tube. I have a customer with an all-tube pacemaker. His heartbeat is steady, reassuring and dependable, not like a modern heartbeat. And if it goes wrong he can fix it himself. You can't do that with SMD." - Mick Bailey

  23. #58
    Member
    Join Date
    Jan 2020
    Posts
    38
    Thumbs Up/Down
    Received: 9/0
    Given: 0/0
    Rep Power
    0
    I’m sorry, would that be on the ICs to look for +/- 15v?

    0 Not allowed! Not allowed!

  24. #59
    Don't forget the joker g1's Avatar
    Join Date
    Feb 2010
    Location
    Canada, somewhere north of Fargo
    Posts
    12,654
    Thumbs Up/Down
    Received: 2,189/24
    Given: 5,521/11
    Rep Power
    24
    Sure, that would be fine. The voltages should come up pretty much instantly when power is turned on.

    0 Not allowed! Not allowed!
    "Everything is better with a tube. I have a customer with an all-tube pacemaker. His heartbeat is steady, reassuring and dependable, not like a modern heartbeat. And if it goes wrong he can fix it himself. You can't do that with SMD." - Mick Bailey

  25. #60
    Member
    Join Date
    Jan 2020
    Posts
    38
    Thumbs Up/Down
    Received: 9/0
    Given: 0/0
    Rep Power
    0
    Went through and inspected solder on both PCBís and some of the connections have ne a little puzzled. More than one have pads essential close enough to touch each other but with my poor eyesight, not 100% certain. I am assuming they are on the same circuit verified by shining a flashlight through the board to see the trace.

    R-57 and R58 on the tube PCB did not seem to make a proper connection so I reflowed them. Previously that tube V3 wasnít lighting, after reflow, cane right up although with a different 12ax7. Initial playback sounded better but the boss that controls the household volume denied he a long play session.

    D likely replace r57/r58 if I could just pick them up in Atlanta area. No such luck.

    0 Not allowed! Not allowed!

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Damn you Blackstar!
    By Randall in forum Maintenance, Troubleshooting & Repair
    Replies: 11
    Last Post: 06-14-2018, 06:29 PM
  2. getting started Debugging a buzz/hum (AB763 deluxe, new build)
    By mikepukmel in forum Debugging Your Build
    Replies: 60
    Last Post: 12-10-2017, 11:58 PM
  3. damn, that's a shame!
    By Randall in forum Maintenance, Troubleshooting & Repair
    Replies: 62
    Last Post: 02-04-2015, 11:24 PM
  4. Damn you DiMarzio!
    By Steve A. in forum Guitar Tech
    Replies: 1
    Last Post: 05-04-2014, 06:37 AM
  5. Damn Generators!!
    By lowell in forum Maintenance, Troubleshooting & Repair
    Replies: 3
    Last Post: 08-22-2013, 12:01 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •