Recent content by Hawkeye351

Odd thing is, after I replaced the 7222 IC, then the volume came up slightly but transmit audio dropped out completely (still a carrier, but not modulation now) and the added talkback switch shuts receive down completely when flipped on (didn't do that before swapping out IC8). I figured the...

"I don't see C180 on that list, its a tantalum cap." , Brandon I see C180 location but there's nothing there. The schematic shows a tant at C180, the parts layout shows a tant at C180 but the cap list skips from C179 to C181 and doesn't list C180. Just a silkscreen marking for C180 but no tant...

Just got back on it today! Signal generator shows great sensitivity. Replaced: IC8 TA7222AP Replaced IC7 JRC4558 Q17 Q44 D16 D17 C80 C170 C172 C175 C179 C181 C182 C186 C187 C243 Receive volume still low in all modes, including PA mode with speaker plugged into PA jack. When I crank volume up...

I don't have 8v on either side of R233. I get 8v on the collector of Q17, but not on either end of R233. This is a different Q17, the old one had an HFE of 34, which I figured was too low, so I replaced it with another one with an HFE of 82.

I still do not have 8v on the RF gain control. Most I ever see on the RF gain control on this radio is 3.36v on any lead. R233 shows 3.36v on one end and 0v on the other, when I turn the RF gain down then the control has no voltage on any lead. Shows as a 1k ohm (in circuit). Replaced Q17 with...

Tested them in my TC1 tester. They showed about 640mv, I think

Yanked out Q17 and D16/D17. The transistor tested fine but with an HFE of 34. According to the datasheet the minimum HFE for a 1674 should be no less than 40. The two diodes tested fine as zeners.

Now I'm getting somewhere on the receive volume. After replacing the 7222 audio IC I checked all voltages on the chip and everything looks right. Although the volume still wasn't quite right, but it is a lot better than it was I rechecked the caps I put in before and checked for bad solder...

By the way, I checked pin 4 after installing this working IC by doing the screwdriver shaft trick and there is a loud ruckus sound when I do that now.

Replaced the audio IC (7222) with a known working one. Still low volume, not as low as it was. Now, I have to turn it up just a little over halfway instead of almost wide open. No more strange issues or sounds when cranking volume wide open, but still low. Voltages now (in correct order this...

Pin 10 lifted: Pin 10 pad shows 0v Pin 10 lead (lifted) shows 10v All other pins still show the same as with pin 10 lead soldered. Shouldn't pin 10 lead (when lifted) be slightly less than pin 1? If the lifted pin 10 lead shows 10v, then wouldn't that mean the 7222 isn't amplifying?

Yea, I measured using board ground, not chassis ground.

I got confused on post 45

Yea, I did lift pin 10. Pin 10 according to the schematic goes through C175 before the speaker if I'm reading the schematic correctly.

I marked pin 1 and pin 10 on this pic. This is the direction I've been measuring. Am I confusing the ends?