The Defpom Forum, for RadioMods, S&M Software and Music by The Defpom

Hi Joe! No problem at all. Yes, if a HAM gives you the report, it explains all :wink: . So tell him that you "only" use an old CB radio. You can align it when it's warm, but you will always have a small drift. Btw that's the reason to use the clarifier on SSB radios :lol: . The person in t...

Hi Joe! 200-300Hz are okay! That's normal for these transceivers. Often they drift a lot more. I have a "newer" Magnum S-9 which drifts nearly 500Hz or more and a Midland Alan87 (SS3900) which drifts nearly 800Hz during warm up. Here you can find the specification of your Uniden: http://ww...

250khz-300khz??? :shock: Wow, that is very much. 250-300Hz are normal. Send it to a rig doctor. He can check all oscillators. Without a good frequency counter it is very difficult to find the reason for this extreme drift. Is it sometimes "on frequency", maybe after switching on? Does it d...

Hi!

How much does it drift? And in which time after switching on?
Does it drift on RX and TX same time?
73s!

NightRanger3151 wrote:Maybe this will help ....

Hmmm...this looks nearly same like President Madison

Hi John,

hmmm...hope that the rig doctor will find the problem. Maybe a small transistor is blown.
Good luck!
73s
Ralf

Hi! On the solder side is a trimmer. There can you adjust the freqency counter. Please adjust it in warm condition with a plastic tool. If you have an external counter, adjust it slightly in TX mode until it matches the right frequency. Maybe you have to align the complete radio in RX and TX. The su...

Maybe you can find some information here: http://www.geocities.com/open_channel/121d4x.html http://www.cbtricks.com/members/rick_euro_radio/cybernet_ptbm121d4x_Part1.pdf http://www.cbtricks.com/members/rick_euro_radio/cybernet_ptbm121d4x_Part2.pdf There are not many info in the www about this board....

Hi John,

i don't really know, but C116 is one of the most problems in such cases. This can't be a big problem, but a hidden one .

73s, Ralf

Good luck to reactivate the good old cybernet!

Strange thing! I think that the microphone is mismatched to your radio. I would go to the dealer with radio & mic to fix the problem.
It is definetly not normal...

Hi!

Check C116 (150pf). This one sometimes blows when the radio is "tuned".

73,
Ralf

Hi again!

RV9 is a 5k b pot!

73, Ralf

Hi!
Here ist the shematic: http://ham-international.nuxit.net/Sche ... TOS012.pdf

Look here: http://malzev.tripod.com/cb-funk/ptbn121.htm

RV9 should be AGC (Automatic Gain Control), hope this helps .

Does the power comes back when the radio is cold? I would check the output transistors & driver at first step too.

Hi the only snag to soldering the resistor inside the radio is my radio is new and has tamper stickers on :( so the mic plug seemed the easiest way but i understand it could be fiddly.What about soldering the resistor inside the microphone as i have taken a look inside the teardrop and i can see th...

Hi,
to do it in the radio is the best way. Other microphones schould not be affected with this mod. I've done this mod in some radios with no problems. I don't know at the moment which pin is ground. Better you look in the manual.
You can also test to choose a ground near the mic socket.
73s, Ralf

Hi! Open the radio and solder a 1k resistor from the audio pin (pin1 if i remember) to ground (pin5). That must fix the problem. Be careful of middle pin6 - there is 12V! This can damage your radio. Or go to the local radio shop. Maybe they can do it for warranty if you explain the problem. 73s from...

Hi guys! What is the correct bias setting for the driver in a EPT3600-14B board. I have a Midland Alan 8001 for repair, same board as SS-3900. The radio works fine but the driver bias was set to ~80mA. I found different service manuals. Some say the driver bias is 10mA, some say 50-75mA. In both set...

Hi David!
Sorry, i've no parts to sell. I have only one adams...
If i will find them i'll mail you!
73s, Ralf

are the CH19/ CH9 not black ones? The scan & normal button are orange.

Does ist have Talkback? Then it could be a 3rd rev.

I think it is better to mount an small CPU fan at the back of the heatsink .
Then the "Magnum" sounds even better
In normal CB use i regular the power output down to 10 watts. Then it is ok with the temperature.
73's, Ralf

Hi, I've a problem with one of my Cobra 200 GTL DX. Due TX the RF power goes straight down from FM 70 watt to nearly 12 watt in HI mode. In LOW mode the power geos down from 30 watt to 8 watt. In SSB mode the max power is nearly the same. In this moments the SBB in LOW power mode the RF power ist hi...

Hi! Is there a difference in quality of the pills? when i go out with 10 watts only it is much better! But the 2230 should make more power i think... is the heatsink to small for the radio? The other version makes 45 watts on FM says the flyer of magnum.

hi @ all! I'm using a Magnum S-9 Radio. The "problem" is, that it runs very warm by using FM or AM mode. The output is normal power of 20 watts. It's the latest variable version of the radio with fixed 20 watts in AM/FM at maximum power (dual finals 2230 MOSFET). In SSB mode there is no pr...

Hi, my name ist Ralf, 29 years old, Callsign 13EL121, QTH Germany, City Duisburg.
Hope to meet some friends here who share my hobby DXing and CB-Radio.
Whish you an nice weekend... 73s!