TM 808 White's

[kt315]

wow.... SMD board =) sweet...

[kt315]

pcb layout

[kt315]

schematic

[dbanner]

If the circuit has 3140 chip then I suspect this is culprit in retune circuit in ground balance channel. It has been known to fail after decades of years

[kt315]

all files on Whites http://depositfiles.com/files/rrw2lafrl

[Orbit]

you know or do not know this fact that TM-808 is a part of 5900/6000 di pro sl, non-motion all metal mode part. ONLY one part.
if you open the schemaic of last you will sure see - +7.5 and -7.5V to gnd will give you 15V.

This would mean that the voltage should be set to 15v ?!
What would be a problem? I have the impression that the geb balance can not be set out on the ground it feels the ground always when I pump down to earth ?
I can not find a balance point !

[kt315]

you know or do not know this fact that TM-808 is a part of 5900/6000 di pro sl, non-motion all metal mode part. ONLY one part.
if you open the schemaic of last you will sure see - +7.5 and -7.5V to gnd will give you 15V.

[Orbit]

Thanks KT and chevesne !
With rv 50 it serves to get a higher voltage at the output on integral circuits ,I'm interested in the output voltage ,I turned the trimmer rv 50 and I get voltage on integral circuits 12 ---- 14v, etc. ,which voltage to set it has at ic ?

[kt315]

4pcs D typo holder. you have 6v or if nicad 1.3x4 5.2v

[chevesne]

You have 6,4v - 0,6v (diode). see the schematic (back left).
So 2,9v between GND and +.

[Orbit]

What is the working voltage for TM808 ?

[kt315]

as veltex was gone... took a money and does not answer. bad.
so slbast made his LAY http://www.md4u.ru/viewtopic.php?f=65&t=9480
check it. enjoy.

[Dest]

Hello, this thread is pretty dead, and is not clear that if anybody succeeded with tm808 schematic . Also I am very interested to build TF900, because the patented version work with 110KHz oscillator, and people in many forums says it is best 2 box detector. For reference in my understandings TM808 works with 13.85Khz, which is far different. Although it seems that Discovery made second version with 2 frequencies - 12.5KHz and 73.5KHz. If I have coils setup I think I can engineer similar schematic that do the same job.
regards
Georgi.

[kt315]

slbast alias does a housing. pics here http://www.md4u.ru/viewtopic.php?f=6...c7699e1239d7ab

[mj620]

Which is the newer / better?
The cave mode tm 808(4 knobs) or 3 knobs tm 808?
Thanks!