The Boogie Board

Discussion Forum for Mesa Boogie Products
It is currently Tue Oct 24, 2017 4:33 am

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 31 posts ]  Go to page 1, 2, 3  Next
Author Message
 Post subject: TC-50 is now Dead...
PostPosted: Mon Sep 04, 2017 1:13 pm 
Offline
Dual Recto

Joined: Fri Feb 22, 2013 7:31 am
Posts: 2507
Location: North Carolina
:cry:

I was setting up do to a recording, had the condenser mics dialed in, was getting ready to adjust the dynamics and then all of a sudden a very loud noise with what sounded like an aching rip of electric plasma discharge through the headphones and noticed the TC-50 was dead. No big deal....wrong... not one "f-ing" store with a 30 mile drive had any of the 2 amp slow blow fuses. WTF.... Spent most of my day searching for a fuse. If Radio shack was still open for business that would have been a done deal in 20 minutes of my time. Had to settle for getting gouged on an assortment of fuses, I see it this way the one fuse I need cost me $10.00 as there was only one in the assortment and the rest are unusable...... bummer. I decided to stock up on fuses for all of my amps, (when Radio shack was open for business I cleaned them out of the 4A slow blow fuses) Had to place an order online though digi-key for a good supply of the 2A slow blow and to get more of the 4A fuses. SH!T happens... no worries about the fuse, just the inconvenience of trying to find them at any local automotive or hardware store. Sure there are plenty of the fast blow fuses, no slow blows to be found at any amperage.... I guess that happened when you live in a dying town, never mind, the entire state seems to be dying. Everywhere you go.... including the fuses I would get the same old thing "oh that is special order....we do not carry such items... I can order it for you and it will be here in three days if you come back".... screw that, I do not mind driving 70 miles one way if you have it.... but not having to repeat the travel again when I could just order it and wait at home.

OK I am done with my rant.... perhaps I got spoiled living in PA most of my life and could find a Mesa amp within 45 minute drive... Now I cannot even find a place that is local to buy guitar strings.... have to order it... perhaps that is the way of life now. I will adjust to that someday as that is what it is....

_________________
Current amps:
TC-50, JP-2C, MK V, Roadster, RA100
Old friends I sometimes miss:
Mk III (blue stripe), Mark IVb-WB


Top
 Profile  
 
 Post subject: Re: TC-50 is now Dead...
PostPosted: Mon Sep 04, 2017 2:00 pm 
Offline
Dual Recto

Joined: Fri Feb 22, 2013 7:31 am
Posts: 2507
Location: North Carolina
Too bad the issue was not as easy as changing a burned out fuse. Did that, also just in case it may be related to the Mesa NOS Siemens tubes I put back the original Mesa EL34s back in before powering it up. All appeared okay that was until I took the amp out of stand-by. Did not blow the fuse but have no sound at all on any channel. I removed the chassis to check the resistor I had replaced that was still good. Now I had to poke around and look for what else may have gone. I will pull the Mesa 12AT7 and try another one. May have to pull one from the RA100..... This time not even a weak signal so something not right here.... sure hope this is not a recurring issue as I like the amp a lot. Is it a lemon? At this point in time may have to decide to send to Mesa for diagnosis. If the 39k resistor is good, will have to check the traces on the other side of the board. If okay, then the and assuming the 39k resistor is on the plate side of the 12AT7, will need to find what is on the cathode which is probably an open circuit. At least I have an RA100 to keep me happy as well as some other amps..... :roll: (but I wanted to use the TC-50.....)

_________________
Current amps:
TC-50, JP-2C, MK V, Roadster, RA100
Old friends I sometimes miss:
Mk III (blue stripe), Mark IVb-WB


Top
 Profile  
 
 Post subject: Re: TC-50 is now Dead...
PostPosted: Mon Sep 04, 2017 4:07 pm 
Offline
Dual Recto

Joined: Fri Feb 22, 2013 7:31 am
Posts: 2507
Location: North Carolina
I have not mapped out the crude schematic on the 12AT7 circuit but that is the problem here.... the 12AT7 is failing.... this time a 220k resistor on the 2nd anode kicked the bucket. Open circuit.... I will have to map it all out to get a better idea of what I am dealing with.... . Probably better to forget it and send the amp off to Mesa for repair... I think the Chinese 12AT7 is not a good choice. why not use a cathode follower that is known to be good like the FX loop used in the Roadster? At least that way all the tubes can be the same.

Bummer the amp is dead.... At least the fuse did not blow when I powered it up.... Everything lights up but no signal. Cannot even drive the power section though the return.. Wonder if the send is working? Have not tried that but I doubt it.

So much for getting a recording of the TC-50 vs the RA100. Second time the amp failed when trying to do this task. Perhaps I should not.....bad omen thing here.

_________________
Current amps:
TC-50, JP-2C, MK V, Roadster, RA100
Old friends I sometimes miss:
Mk III (blue stripe), Mark IVb-WB


Top
 Profile  
 
 Post subject: Re: TC-50 is now Dead...
PostPosted: Tue Sep 05, 2017 5:55 am 
Offline
Dual Recto

Joined: Fri Feb 22, 2013 7:31 am
Posts: 2507
Location: North Carolina
If I wanted an accurate rendering of the 12AT7 circuit I would have to remove the board from the chassis.... It is not all that important at the moment. I did find all of the resistors I need through Mouser including the one I had replaced earlier. Even though that is fine, I would prefer the 1% resistor value of the 39.2K as the 39k 5% measures in at 38.52k where as the other 39.2K seem to have a higher value around 39.85k (depends on what meter I am using and doubt a 4 wire meter would get better results since the parts are in circuit and other components will influence the measurements. So far I found two 221k resistors to be open and one 1M resistor is questionable. Since I repaired the amp the first time, I would be certain with no doubt the warranty is null and void. Had I sent it in for repair it would be going back again due to the recent issue to replace the resistors that failed probably due to strain from the first incident. This time the resistors that were found to be open circuits seem to affect both sides of the 12AT7 tube. Interesting as to what would cause this.... Now I have two Mesa 12AT7 tubes in quarantine so they do not get used again. In both cases when the issue occurred, all preamp tubes were original Mesa tubes. I only have two Mesa 12AT7 tubes left and both are in the RA100's. At least I have a few of the JAN/Phillips 12AT7 and one RFT 12AT7 that could be used. I am not sure I want to repeat replacing components in the amp. At least it is not as crowded as a Mark V so repair is feasible with the right methods of part removal.

What a bummer I was enjoying the amp while it lasted... seems like an easy fix and will hope for the best after that....

_________________
Current amps:
TC-50, JP-2C, MK V, Roadster, RA100
Old friends I sometimes miss:
Mk III (blue stripe), Mark IVb-WB


Top
 Profile  
 
 Post subject: Re: TC-50 is now Dead...
PostPosted: Tue Sep 05, 2017 9:50 am 
Offline
Mark III
User avatar

Joined: Wed Feb 27, 2013 12:45 pm
Posts: 268
Location: Southwest Michigan
That is depressing as hell! Very sorry to hear that, Bandit! I've used mine tons and never had an issue at all. I did blow a fuse in my V, and robbed one from my Dyne until I got an order in. Mesa sells fuses, too, in case you were wondering. I just didn't like their shipping charges and went to Radio Shack online to get my replacements. They permanently closed the storefront where I live. That killed a lot of supplies for me, including solder, extra wire, and terminals. Also sucks that your initial repair voided your warranty! The warranty is the only thing that keeps me from experimenting with different brand tubes. Five years is a long time to wait, but I am being as patient as I can. Still haven't put in the Mesa 5881s yet, even though they are brand new and all pretty and shiny in their Mesa box! I put the factory E34s in for a little while instead. The only other change I've put in mine is the SPAX7 in V1. Hope yours gets back to full health soon!

_________________
__________________
TC-50, Electra Dyne, Mark V, Road King I
Mostly Fenders with Duncans
EVM, Eminence, and WGS speakers


Top
 Profile  
 
 Post subject: Re: TC-50 is now Dead...
PostPosted: Tue Sep 05, 2017 11:41 am 
Offline
Mark IV
User avatar

Joined: Wed Sep 08, 2010 4:12 pm
Posts: 629
Location: Petaluma, California
jnoel64 wrote:
Also sucks that your initial repair voided your warranty! The warranty is the only thing that keeps me from experimenting with different brand tubes. Five years is a long time to wait, but I am being as patient as I can.


Yes, that is unfortunate. In any case I'd definitely recommend a factory repair, so you can be sure the correct issue is being addressed.

_________________
MESA/Boogie - Product Specialist/Customer Service - http://www.mesaboogie.com/support/index.html


Top
 Profile  
 
 Post subject: Re: TC-50 is now Dead...
PostPosted: Tue Sep 05, 2017 12:02 pm 
Offline
Dual Recto

Joined: Fri Feb 22, 2013 7:31 am
Posts: 2507
Location: North Carolina
I was able to locate the equivalent resistors. If I have another issue I will send in for repair. I would suspect the parts have been compromised as all three resistors are associated with the Anode, two of which are associated with the same circuit that failed previously. I suspect the 12AT7 tube to be at fault and on each occasion I had two different 12AT7 in V5 as I did not reuse the one that cause the issue after the repair. Second one was New still in box Mesa 12AT7. This last occurrence the current draw must have been strong enough to burn the fuse open. I may open up the RA100 just to see how different the design of the FX loop buffer circuit is. I would assume it is about the same but without the relay.

Since the first issue, it was disappointing....but the fault was easy to discover. Perhaps the root cause is still unknown. If the repair does not fix the issue perhaps I will donate the amp to Mesa for RCA. (root cause analysis) regardless of the warranty. I will pay for repairs and such but depends on estimate as it may be cheaper just to get another one, which I was considering but..... is there a problem that needs to be discovered? And if I get a new one, will it happen again? Great sounding amp and a feasible solution to this issue would be great if it is an issue in design or component flaw that may affect more than one. Tube fault seems to be likely cause but resistors should not go first before the fuse. It happens but with a preamp tube.... I will hold onto the 12AT7 tubes in question in the event I ship the amp back for analysis. I would prefer to return it to the source (Mesa) as offsite service centers may not report the needed information if a change is required.

_________________
Current amps:
TC-50, JP-2C, MK V, Roadster, RA100
Old friends I sometimes miss:
Mk III (blue stripe), Mark IVb-WB


Top
 Profile  
 
 Post subject: Re: TC-50 is now Dead...
PostPosted: Tue Sep 05, 2017 5:55 pm 
Offline
Dual Recto

Joined: Fri Feb 22, 2013 7:31 am
Posts: 2507
Location: North Carolina
Change of plan.... just send it in for analysis and repair. Warranty is null and void since I had worked on the amp myself. Recommendation, it if looks easy enough to fix, do not bother as you are only correcting the end result of something else that caused the issue and voiding the warranty in the process.

All depends on what the estimate for the repair will be and will have to evaluate if it is worth the additional cost plus the original purchase price compared to just getting a new one to replace it. Will have to wait and see what happens next.

_________________
Current amps:
TC-50, JP-2C, MK V, Roadster, RA100
Old friends I sometimes miss:
Mk III (blue stripe), Mark IVb-WB


Top
 Profile  
 
 Post subject: Re: TC-50 is now Dead...
PostPosted: Tue Sep 05, 2017 5:57 pm 
Offline
Mark IV
User avatar

Joined: Wed Sep 08, 2010 4:12 pm
Posts: 629
Location: Petaluma, California
bandit2013 wrote:
Change of plan.... just send it in for analysis and repair. Warranty is null and void since I had worked on the amp myself. Recommendation, it if looks easy enough to fix, do not bother as you are only correcting the end result of something else that caused the issue and voiding the warranty in the process.

All depends on what the estimate for the repair will be and will have to evaluate if it is worth the additional cost plus the original purchase price compared to just getting a new one to replace it. Will have to wait and see what happens next.


I wouldn't blow it up more than it is....lol. Its a simple fix, just needs to be done right...and will be a minimal repair cost. We'll have it turned around in no time...Thanks!

_________________
MESA/Boogie - Product Specialist/Customer Service - http://www.mesaboogie.com/support/index.html


Top
 Profile  
 
 Post subject: Re: TC-50 is now Dead...
PostPosted: Tue Sep 05, 2017 8:57 pm 
Offline
Dual Recto

Joined: Fri Feb 22, 2013 7:31 am
Posts: 2507
Location: North Carolina
Great. Nice talking to you on the phone today.... Yeah, it is what it is.... I am sure it will get fixed properly. Too bad I cannot come with the amp as that would be an ideal trip for me... I will stay home and wait as I will not fit in the box with the amp. I will be looking forward for the amp's return.

I would like to know what the root cause of the issue is, perhaps your suggestion was on the money but wait and see when it gets there.

_________________
Current amps:
TC-50, JP-2C, MK V, Roadster, RA100
Old friends I sometimes miss:
Mk III (blue stripe), Mark IVb-WB


Top
 Profile  
 
 Post subject: Re: TC-50 is now Dead...
PostPosted: Wed Sep 06, 2017 12:26 pm 
Offline
Dual Recto

Joined: Fri Feb 22, 2013 7:31 am
Posts: 2507
Location: North Carolina
Considering what has happened, this issue should be considered as a rare or unlikely problem and I doubt it is something to be concerned about.
I will chime in when I get it back, It shipped out this morning and should arrive at Mesa by Wednesday next week. Packed it up in original shipping carton. Shipped insured to the replacement cost in the event of a loss during shipping. I was not expecting the sticker shock on the shipping fees, ouch. Insurance did not add that much to the cost so was worth it.

_________________
Current amps:
TC-50, JP-2C, MK V, Roadster, RA100
Old friends I sometimes miss:
Mk III (blue stripe), Mark IVb-WB


Top
 Profile  
 
 Post subject: Re: TC-50 is now Dead...
PostPosted: Wed Sep 06, 2017 1:42 pm 
Offline
Mark III
User avatar

Joined: Wed Feb 27, 2013 12:45 pm
Posts: 268
Location: Southwest Michigan
I am definitely interested in an update! Taking mine out for a workout tomorrow with my new (to me) vertical 2x12. I will finally get an opportunity to hear the amp at an appropriate volume and in a full band setting. For now, all my tubes are stock Mesas, including the SPAX7 in V1. I put the EL34s back in specifically for not only this meeting, but also for the increased headroom when using it in my other band setting, even though that band only gets Ch 1 used. Depending on the outcome of tomorrow night, I may put the 5881s in for the other band. I think that would be the most ideal setup for that group.

Hope yours gets fixed soon! I would cry if mine failed.

_________________
__________________
TC-50, Electra Dyne, Mark V, Road King I
Mostly Fenders with Duncans
EVM, Eminence, and WGS speakers


Top
 Profile  
 
 Post subject: Re: TC-50 is now Dead...
PostPosted: Wed Sep 06, 2017 6:08 pm 
Offline
Dual Recto

Joined: Fri Feb 22, 2013 7:31 am
Posts: 2507
Location: North Carolina
Joe,
I doubt there is reason for concern. Life seems to hand me lemons.... If they are too sour I may do something about that. At least the TC-50 was a sweet lemon... unlike the Mark V that left me sour in many ways. Hopefully the TC-50 will be a peach when it comes back and not a bitter apple, could go for some melons as well. Still things will turn out for the better and would rather have the issue resolved vs replacing the side effects. Chance it may be a dc blocking capacitor is high.... The amp will arrive by Wednesday so all is good.

I may just pick up another one just so I have two. The combo sounds interesting but been there done that already having the RA100 head and combo it gets confusing as one is inverted vs the other and the manual was written on the bias of the combo, not hard to invert mentally. I do cherish both even though they were adopted models and not new born deliveries. One did need a little bit of repair and is in need of a new power tube board or at least the sockets replaced as the original owner must have drilled them out or attempted to widen the guide hole since the key is basically missing, just a halo of where it used to be so I marked it with a black marker to find it and have to power up the heaters to confirm the tube is indexed properly. That one should get a trip to Mesa for an update (it works well but tubes could be easily inserted incorrectly). Perhaps one day. I have also found where someone had made a repair on the circuit board. I can tell poor workmanship from good. Correct parts are in place as I had the Combo to compare it too and that board appears to be untouched. Everything is working find there so no need to correct the sloppy workmanship.

The RA100 combo is basically mint but does have a mod done to it (the input was routed to the rear of the amp with an additional cable and jack). Probably so they could run a 4 wire hook up pedal board or something. I can live with that as it does not seem to pose any problems. I would prefer to buy new than used as often times there have been mods or changes by the previous owner.

TC-50 should be as good as new or better when it comes back. I will also have the ribbon mic for better recording so may go back and repeat the Mesa stock tube comparison again. Not sure if I will entertain the other at the moment.

_________________
Current amps:
TC-50, JP-2C, MK V, Roadster, RA100
Old friends I sometimes miss:
Mk III (blue stripe), Mark IVb-WB


Top
 Profile  
 
 Post subject: Re: TC-50 is now Dead...
PostPosted: Wed Sep 06, 2017 8:22 pm 
Offline
Mark II

Joined: Sun Feb 02, 2014 11:51 am
Posts: 95
Good luck getting it fixed. When I shipped in my Mark V head I used original packaging and Mesa decided to keep it, even though there was a big note in there asking to return it in the same packaging. And yes, there was a sticker shock with the shipment cost!

Quote:
Yes, that is unfortunate. In any case I'd definitely recommend a factory repair, so you can be sure the correct issue is being addressed.


This post seemed a bit ominous. I've surfed this board a lot in the past year and I've never seen Mesa post in any of the threads I read. When I read Bandit's post I'm thinking "hmmm, can he send it in for warranty anyway even though there is an extremely detailed list of all warranty breaking activies documented here? Could Mesa put 2+2 together?"

Then I saw this post and it cracked me up. In my head was Darth Vader's voice. "I find your lack of faith disturbing."

:P


Top
 Profile  
 
 Post subject: Re: TC-50 is now Dead...
PostPosted: Thu Sep 07, 2017 5:58 am 
Offline
Dual Recto

Joined: Fri Feb 22, 2013 7:31 am
Posts: 2507
Location: North Carolina
Authorized Boogie is real.... when I called customer service and spoke with the individual taking the call I asked if he was Authorized Boogie since he immediately knew what the issue was when I called as he referenced this thread. Is reply to the question was "yes". I would not doubt that there may be others in the customer service that may post in threads as "Authorized Boogie" or it may just be one person.

_________________
Current amps:
TC-50, JP-2C, MK V, Roadster, RA100
Old friends I sometimes miss:
Mk III (blue stripe), Mark IVb-WB


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 31 posts ]  Go to page 1, 2, 3  Next

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group