One of my locals got this radio on ebay with power supply problems and after fixing (avr) the power supply replacing Q13, Q6, D1, D2, D14, D3, and D9, the radio starts and after testing on a dummy loan the radio swings about 80 watts. but heres the trick, the radio transmits about 5-20 minutes and the frequency display goes out and all i see are dots. after a while the radio comes back sometimes/sometimes not. and then i decided to search online and i got some ideas on how to go about fixing this problem. after i started pinpointing, and testing all the connections, this is what i got. can someone help me out fixing this problem?
i think Q31 and 32 is the problem but i cant find it in any stores, what do you think?
kenwood ts-940s serie708xxxx
pll 50-2020-00 board
ic19>pin2=4.82v
ic8>pin2=1.37v not working (1.8vworking)
d16 ok
d8 ok
r75=2.34v (4.8v)
ic9>pin2=4.76v
ic9>pin3=1.46v
ic17>pin7=5.10v
ic17>pin1=2.28
ic19>pin3=1.59
d9=4.75v
con 5 pin4(ul)=0 (4.8v working )
con 2 pin5(ul)=2.49
d16 ok 2.50v/4.84v
Q 31 = DTC124ES NPN(NTE2357)
IN | OUT | GROUND |
3.90 V | 0.02 | GROUND | NOT WORKING
0 | 4.84 V | GROUND | WORKING
Q 32 = DTA124ES PNP(NTE3258) DIGITAL TR
IN | OUT | VCC |
2.49 | 4.92 | 4.9 V | NOT WORKING
4.91 | 0 | 4.95 | WORKING
i think Q31 and 32 is the problem but i cant find it in any stores, what do you think?
kenwood ts-940s serie708xxxx
pll 50-2020-00 board
ic19>pin2=4.82v
ic8>pin2=1.37v not working (1.8vworking)
d16 ok
d8 ok
r75=2.34v (4.8v)
ic9>pin2=4.76v
ic9>pin3=1.46v
ic17>pin7=5.10v
ic17>pin1=2.28
ic19>pin3=1.59
d9=4.75v
con 5 pin4(ul)=0 (4.8v working )
con 2 pin5(ul)=2.49
d16 ok 2.50v/4.84v
Q 31 = DTC124ES NPN(NTE2357)
IN | OUT | GROUND |
3.90 V | 0.02 | GROUND | NOT WORKING
0 | 4.84 V | GROUND | WORKING
Q 32 = DTA124ES PNP(NTE3258) DIGITAL TR
IN | OUT | VCC |
2.49 | 4.92 | 4.9 V | NOT WORKING
4.91 | 0 | 4.95 | WORKING
Last edited: