TM Deluxe 40 Anode Fuse?!

Hi,

My Tubemeister 40 shows all 4 tsc lights lighted Up in red.
No more sound.
I gave it a try and changed all valves (No more warrenty).
Same problem as before.

I experimeted not in a very wise way when the problem occured.
I put a volume pedal in the fx loop and played arround.
Then it happened.
All 4 lights red. No more sound.

Does anyone have an idea what the proble may be here?
Might it be the anode fuse as described in the manual?

What could be done?

Cheers

I found it. A 400 mA fuse was blown. Lets See...

Looks like you sorted your own problem FD. Be careful with the case open. Did you use the correct method for opening it so as not to void the warranty? Yours is out of date but others reading this might benefit.

On both end caps, remove the top two screws completely. Only remove the rear middle screw and leave the front alone, it does nothing except hold the handle on. LOOSEN BUT DO NOT REMOVE the lower two screws until the end cap flops outwards enough to remove the cover. This leaves the anti tamper indicators inside the amp undamaged preserving the warranty.

The HT fuse MUST be the correct 400mA. Don' try to replace it with "one I had handy". The fuse has blown. That means something went wrong. Hopefully it is now ok but it may be a permanent fault. A higher value fuse may not give the protection it should when you switch on again and more serious damage could occur. That could be to you! It is always worth buying a box of the correct fuses to be sure to have them to hand just in case.

I don't see what a volume pedal in the loop could have done to cause an HT fuse to blow. The most likely problem would be a valve fault. Anyway, hope it is up and running again now.

Thanks a lot for your detailed comment!
Until now everything seems to work fine.
I am really amazed what (good) difference the new valves for the preamp make.
I simply chose tad tubes which were recommended for Tubemeister 40 Deluxe (non metal recommondation).
Only thing i notice now is that if i turn off the "Play" switch still some tiny ammount of sound is comming through if i strum a chord for example.
Is that super "not normal"?
Do you know anything?

That residual sound when the Standby is engaged is absolutely normal Fujigen. Most amp Standby systems work by removing the HT from the output valves, (and sometimes the PI valve too). This means the valves can pass absolutely no current at all and completely silences the amp. It also leaves the heaters working so the valve is ready to go at the flick of the switch. It is VERY BAD for the output valves to do this and it gradually poisons them and kills their action. It started as a mistake in the original guitar amps and has carried on because now guitarists "expect it". It is even the case that the original Vox amps had no Standby and worked perfectly. In response to the other makes having Standby Vox added it in in their later models and they actually were known for blowing PSU components through it. Standby on "classic" amps like Marshalls and Fenders should not be used. I always ask, what is wrong with simply turning the MV fully down? Valves do not "wear out" when they are left simply idling like that. They die when they are left emitting electrons with no means of clearing the electron cloud from around the cathode, i.e. heated to temperature but with no anode current running.

The H&K Standby is a completely different and more modern system. It uses the TSC circuitry in the valve cathodes to restrict the current to a very low level preventing them from amplifying the signal. Leaving a small idling current means the output valves do not suffer the same damage but it does mean that there will be a tiny headroom left for signal amplification and that is what you are hearing. It does seem to vary from amp to amp if you listen to people's varied level of complaint according to perhaps component tolerances, although it could just be that some people are more annoyed by it than others.

I'm sure you yourself are just curious about it but I have to admit, I'm never clear as to why some people get very upset over this and seem to think it is an appalling mistake in design which ruins a good amp.

Thanks a lot for your reply!!

Hello guys
My tubemeister deluxe 40 also died a couple of days ago.
The HT fuse was blown. I've tried to replace and and even replace 2 Power Tubes(older tubes that aren't that great) and it still seems dead.
No lights or anything, completly dead.
I don't know, could it be that all the power tubes are dead? Or maybe the Preamp Tubes?
I've changed the tubes in March this year withsome TADs.
Any help is very much appreciated!

Hey,
If you can't see anything this is a hint that that the main fuse has been blown.
You can check that in a simply easy way'
Below the place where you put in your Power supply cable there is a tiny drawer where the main fuse can be put in and out.
In most cases you can see if a fuse has blown.
Never operate on electric devices without the necessary knowledge about it's components.

Hi guys.  I've moved this topic into the Tubemeister forum.  It concerns the fuses in the TM40D.  These will be different to the lower powered versions and that should be borne in mind in order to prevent confusion if others read it looking for specific TM20D info.  Confusion with fuses is not a good thing! Continue as normal here in what seems to be the best place.  The forum titles are a bit ambiguous, I'll see if I can sort that out too, (have changed them but it isn't absolutely clear with the 5/18/36 and 20/40 designations).



Ok FenderBender.  First you have replaced the HT fuse which is good.  If the amp as you say "still seems dead" I will assume you mean that nothing AT ALL happens at switch on.  That means that the new fuse you put in the HT slot is still ok after switch on with no response?  Knowing that is important because, if it blows, then it means your mains fuse in the slot Fujigen has pointed out is still ok.  If the new HT fuse stays intact at switch on then the mains fuse could well be popped as well.  That should be checked and you should really check fuses with a continuity tester like a meter or a screwdriver with an indicator in it.  Fuses do often break or blow inside the silver end caps and show no signs of being broken in the glass portion.  They don't always go with a pop and a big black smudge, sometimes they just part company with a non-visible break in the filament.

The most likely thing to cause this is an output valve fault.  They can go short inside due to faults like debris from manufacturing.  ALL valves can do this so don't believe that there are any magic makes which never give a problem.  Fitting known good ones which may be a bit soft but have proven themselves to be working as you did is a good test for the fault.  TAD are a major rebrander of other maker's valves, as far as I know they don't make their own.  I believe theirs used to be sourced from Shuguang in China.  As people point out, this can be bad, they could just pick up any cheap junk no one else wants, or it could be good, they could specify better than standard spec selected from the production line.  Do you get them cheaper from TAD or more expensive?  I don't know, but people will believe what they want to on this point just as they do with all valve information despite the facts.

First check the mains fuse and replace if necessary.  ONLY WITH THE ABSOLUTE CORRECT ORIGINAL SPEC.  Your fuse is a safety device designed to a) keep you safe (alive!), b) prevent damage to your amp under fault conditions.  If you put in the wrong spec you could compromise either or both of those aims, especially if you are replacing one which has blown because there is definitely something wrong as in this case.  The fuse spec should be stamped into the silver end cap and is as follows:  'T' - Slow Acting (as opposed to the other designations for very slow through to very fast TT, M, F, FF).  250V - pretty much standard and is the minimum, figures above this would be fine.  630mA, 0.63mA, 1A, 1.25A - the current at which the fuse should blow and this should be seen as the ONLY correct value to fit.  L - Low Breaking capacity (as opposed to H high).  My advice is, get a box of the correct fuses for your amp and never be caught out again.

Depending on where you are in the world the correct current value varies.  Just for clarity the values are as follows copied from the TM18 manual (remember this when you read my final point):

Mains fuse, 100 volts	250V / T 1.25A L
Mains fuse, 120 volts	250V / T 1A L
Mains fuse, 220-230 volts	250V / T 630mA L - (same as 0.63A)
Mains fuse, 240 volts	250V / T 630mA L - (same as 0.63A)]

The internal fuses are not given in the user manual as the idea of non-qualified personnel opening up the amps is something H&K discourages, understandably.  I will give them here as most people will do it to look for themselves whether they have the correct rating or not.  REMEMBER, IF YOU OPEN UP YOUR AMP YOU WILL VOID THE WARRANTY AND PUT YOUR HEALTH AT RISK.  You take that on your own head, do not blame me if you get killed!  Ok, that said there is a HT fuse (FU1) and a LT fuse (FU2) in there.  That's a high voltage one for the valve line voltages and a low voltage one for the solid state circuitry.  All countries will share the same values as it is after the mains section but those values will vary according to model.

TM36/TM40D, HT FU1	250V / T 400mA L
TM18/TM20D, HT FU1	250V / T 200mA L
TM36/TM40D, LT FU2	250V / T 800mA L
TM18/TM20D, LT FU2	250V / T 315mA L

When you are changing these fuses you can easily make direct contact with the voltage line they protect.  That means you are touching parts which carry almost 400V in the case of the HT.  Most amps have drain resistors fitted to remove this voltage after switch off but this can take time.  Leave a little time between switching off and making a replacement for the voltage to drop to a safe level.  And for the record, bear in mind some other makes of amps may not have those resistors fitted.

Last thing I have to say.  These values are taken from the couple of service manuals I have access to.  That is, for the GM36 and the TM18.  The GM40D and the TM20D and any other variants in the same family with the same power should be very close to that, maybe even exactly the same (as I would expect).  If you have to replace your fuses from that information, check out what you find there and, if it is different to what I have posted, come back to us on it for clarification.  If I am wrong in what I am advising we must know and I must correct it.  Otherwise, if you find something different, it may be a VERY BAD replacement by someone before you which should be corrected.

Keep us up to date with the problem.