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The TDA2003 is a "Hi-Fi" amplifier, with better THD specs than the TA7222ap, many car stereo circuits use greater than 470uF on the output.
The transformer in the radio will reach saturation point quickly if you attempt to pass too much low-end bass response through it.
The components tied to...
Robb, check for any removed parts "downstream" of the output capacitor.
A good friend of mine with experience using the TDA2003 told me to verify the presence of a "nuetralization circuit" (tube reference) after the output capacitor.
Without referring to the datasheet, it could be a low value...
Robb, I've been a bit scrambled lately.
The clarifier was off-center after it was all said and done, values needed to be changed in the circuit. If you tuned the clarifier far-left it would pull too hard on the vco causing the pll unlock!
Sorry, I don't recall the Kenwood.
Before "downloads.cobra.com" quit working I believe the 25 LX schematic was available (also 29 LX). I have a copy saved but cannot access it a.t.m.
Not the same I.C. but still relevant;
I've seen more than a few TA7222ap audio chips produce self-oscillation (and subsequently heat) when powered...
At first (because of loss of TX/Lock issue) I suspected the clarifier mod was causing VCO to quiet oscillating.
I will have to go through entire alignment procedure and see if the VCO Card is causing an intermittent failure (if the radio "fails" and acts strange again).
It could be that there...
Checking Pin 8 of IC3 for 10.2400
My friends vintage counter read 10.2394XX instead of 10.24000.
I believe the counter was loading the oscillator, causing an inaccurate measurement;
Those Chinese test leads offering a simple direct current path to the BNC input.
After reading some posts...
Thank you.
I did not short R174, and left the yellow wire alone (believe a resistor to gnd is down circuit on pcb)..
I will inspect to make sure the resistor is actually in circuit and not bypassed, thank you Andy!
Radio had been through the ringer, changed electrolytic and tantalum capacitors, rebuilt PSU and PA.
Everything seems to work ok, though it's one channel low & occasionally won't transmit. I can get to 27.285 by going to Ch. 29 and adjusting clarifier.
Now and again the frequency jumps, I...
(For some people) this depends upon whether or not the AMC has been defeated..
You may hear some people talk about a "sweet spot" for the mic gain, this can be indication of a "clipped limiter" (or disabled automatic modulation control), though this isn't always the case.
Often times an...
No conspiracy, just my opinion..
For all I know his phone number & address may have been posted publicly at one time, but I don't see that info posted on his YouTube channel.
Sometimes people need a break, sometimes life gets in the way..
For all we we know, the "Greys" could have kidnapped...
Mike knows his email address is public, releasing anything beyond that (without his consent) would be tantamount to doxxing (IMO)..
I hope he is doing well wherever he may be, I miss his YouTube channel; he's one of the few on YouTube that I enjoyed listening to.
(y)
The 2SC945 was a fairly common NPN transistor, I believe the "A" signifies that it's suitable for Audio Frequency amplification (& low speed switching);
"Q" denotes classification of hFE, Q would be an hFE range of 135-270.
To avoid weeding through the mountain of fake parts commonly found...
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