Tube Amp Archive

Much time is gone but no one post the JTM145 Tone stack board and Input Board...

Hey guys I forgot to put here but I have it written in a paper: int he JTM1:

C301: is written: 4 (than a space) 7 all this has a line under it.


Bye

Thanks Matec, I did my best. Your schema was already almost perfect.

Yesss, the other 1 W!!!! Like the JTM145, the best in my opinion!!



Bye, jazzkramer

Hi Matec, I think I tried with the 1W and with the 0.1W setting and it was always ZERO. I forgot to put a jack inside the two speaker out so, maybe they were connected to the mass... don't know. I remember trying to check your schema in this section I had various problem: my tester is not respondig ...

Hi guys, just checked all resistor values, even if was probably already known. I checked by tester and I copied the colors. N.B. 5 colors resistors may have color spelling reversed (becouse I don't know the color code without checking). Some of the resistors result in ZERO ohm by tester, but I think...

Hi Matec,

I think in the 145 there's C12 is added as well near the output jacks, of course I don't know the value.

Bye, jazzkramer.

Hi guys, I almost checked all the board. Matec you are great, the last schema seems correct. The diodes bridge has different names, but it's the same I mean, if you want, in your schema from top, the first is D4 the second D2 the third is D1 and the forth is D3, the fuse is not in that position but ...

Sorry guys, I have some unespected problems in these days, I'm late with all the jmt1 test and schema check, I will do as soon as possible

Bye, Jazzkramer

Hi guys, Sorry, I can't unsold anything on the board because the JTM1 I have is not mine and I don't want to compromise the warranty or worst, damage it. (And I don't find my solder, here I'm a host, my home is 10K km far from here). I don't have any AC transformer, but maybe I can do something diff...

Hi Matec, hi guys, I confirm R9 is by tester 56,2 Kohm.
This night I probably have no time to go on checking the schema, but I will finish it in the next days, we need it!

Bye, jazzkramer.

Hi MHProd, thank you, I think at the moment we don't. I have a JTM1 board in my hand and I'm trying to check Matec schematic.

We would need JTM145 tone PCB photos and input PCB both sides.

Thanks, bye, jazzkramer.

Ok here are the progress.... Now going to sleep: In green the checked part. The part between V2B and V3 seems to me very different. I'm too tired to make a better drawing now, I will do after finishing checking. Maybe I mistaken something, I will re-check everithing. I'm not checking any component v...

Ok Matek you did a great job! All the green part is correct while it seems that in the components between V2B and V3 there are some mistakes. I will better check but now I have to stop. To better verify, I ask you if you can maybe post a better resolution image, I mean it's not simple to read all th...

Ok: so I put one of the tester probe to the middle pin of the CON101 the other tester probe: (I spell terminas as if you where looking to the amp from the front, when all assembled) C103 Upper terminal infinites ohms; down terminal 12,1K R101. right term reads 12,1K; left term reds 112,6K R103. Uppe...

Yes Matec sure. I'm little busy with other things, so maybe I will not reply soon, but tell me :wink: And, checking the main board, at the moment I found a little difference: So: The green area is already checked. The purple wire is the one I see in the board and not in your schematic, so I added it...