Thank you for your reply.

But, someone would have to take a fair amount of time to try to figure
out which parts control frequency from looking at it. "Blue caps"
don't mean anything - one has to trace the circuit to determine what
the components do.

You are right. I tried to find the schematic on internet with no luck. If I
try to trace the schematic it will take much time, because I don't have much
knowledge in electronics, none in oscillators. For me, it will take two
days... I'm sure, you know, someone without knowledge may needs 20 or 50
times more time and effort to find what he wants.
If you could guide me to trace a very small part, I will.
The model is the CD-2800, CODYSON (China) is the manufacturer.
The only info I found on internet are the following. I don't know Russian, I
tried to register but it has a quiz of 15 questions:
http://www.mcrf.ru/forum/showthread.php?p=123710
http://www.mcrf.ru/forum/showpost.ph...&postcount=228
Registration -- http://www.mcrf.ru/forum/register.php

p.s. If the above forum has the schematic, may it worth to find it first.

--
Yianni

(Remove the number nine from my email address to send me email)




"Samuel M. Goldwasser" wrote in message
news

"William Sommerwerck" writes:

"Yianni" wrote in message
news:1218677883.639830@athprx04...
"William Sommerwerck" wrote in message
. ..

The transducer is probably highly resonant at the operating frequency.
If you change the frequency, output is likely to be greatly reduced.

I don't think the transducer is so high resonant. At least the specific
one.
On the other hand, I would like to try. Do you know which parts to
change?


I'm going to be nasty. What needs changing is your attitude.

Why are you wasting our time? You haven't supplied a manufacturer or a
model
number, or a place to find a schematic. Why do you think anyone would
have
the knowledge to suggest a specific change for an unknown product?

Furthermore, the answers I and others gave were "reasonable" in the
context
of the question you asked and the overall design of such products.

If you know so much about the unit, modify it yourself.

To be a bit more diplomatic , the OP did supply photos of the PCB.

But, someone would have to take a fair amount of time to try to figure
out which parts control frequency from looking at it. "Blue caps"
don't mean anything - one has to trace the circuit to determine what
the components do.

If the OP would do that and post a schematic, or even a partial
schematic, then someone should be able to help.

--
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