Galaxy 88hl TX issues

[rockinredsrooster]

Good day, I have a galaxy 88 which does not transmit. So far I have replaced the finals and driver hoping to end this repair with an alignment.
Given that I'm an amature, here's what I have come up with so far.
The regulator tr-51 is ok, Tr-36 has the correct voltage, tr-41 correct as well.
With the radio on SSB, I find full voltage at the driver and finals but this is not the case for the other modes.
If anyone has a good suggestion, please post it. I will run through the alignment process in hopes of isolating the problem.
help Ole Chicken-man out here.

[Rick]

What is the voltage at TP9 in TX on AM, FM and SSB, and what is the Base and Collector voltage of TR45, TR44, TR45 and TR56. Can you adjust bias on TR 44 (VR11), TR43 (VR10) and TR56 (VR20), if not le me know which one you can not adjust. Let us know how you get on.

[rockinredsrooster]

Rick, I will take those measurements later this morning to post here. I appreciate the help.
Rooster

[rockinredsrooster]

Rick TP-9 AM=6.75v FM=6.75v SSB=13.8v
Driver sc2166 replaced with substitute sc1306
TR-44 AM(B)=.62v (C)=6.86v
TR-44 FM(B)=.67v (C)=6.8v
TR-44SSB(B)=.68v (C)=13.8v
Final sc2312
TR-43 AM(b)=.16v (C)=6.86v
TR-43 FM(B)=.16v (C)=6.8v
TR-43SSB(B)=.16 (C)=13.8v
Final sc2312
TR-56 AM(B)=.10v (C)=6.86v
TR-56 FM(B)=.16v (C)=6.8v
TR-56SSB(B)=.11 (C)=13.8v
Pre-Driver sc2538
TR-45 AM(B)=1.17v (C)=8.40v
TR-45 FM(B)=1.17v (C)=8.4v
TR-45SSB(B)=1.8v (C)=8.41v

[rockinredsrooster]

I will try adjusting the Bias for the listed transistors. I will post the findings shortly.
Rooster

[rockinredsrooster]

I will try adjusting the Bias for the listed transistors. I will post the findings shortly.
Rooster

Bias is showing 70ma, final Bias is showing 0ma current?

[Rick]

So let me get this right, with you DVM set to ma, the bias current from TP9 to TP8 is 70ma and from TP9 to TP7 is 0ma, his this right?

What is the voltage at each side of R217, R218, R129 and R272?

The problem is that TR43 and TR56 are not being turn on.
Check for cold solder joints around the PA stage.
2SC1306 is not the best transistor to as it requires a lot drive, it was ok in old radio.

[rockinredsrooster]

Rick, others, I now have the proper idle current at the driver and finals but still no output. Checked voltages at IC 9. Bear in mind I know very little but it seems to me that IC9 is not receiving a signal? Any further help would be greatly appreciated.

[Rick]

What is the bias current on the Driver and Finals?
What make you think there is on signal at IC9?
Do you have a standalone frequency counter?

[rockinredsrooster]

Driver current 70ma finals 97-99ma
A friend of mine has a device used to detect RF, he said no signal was present at IC9?
I do have a freq counter, I will connect it later to see what is at the test point/s.
I appreciate the help for certain but I'm almost at my rope's end. Had this radio belonged to me, trash collection would now own it. A neighbor asked me to look at it a long time ago, it ended up on a shelf forgotten about until recently. I had hoped to return it working after having it so long.
Could the audio amp IC8 cause the symptoms I'm seeing? Reasoning, the audio IC has had the mounting screw stripped preventing thermal conduction with the chassis. It's hanging loosely against the side. The radio is switching TX RX and does produce talkback audio as well as PA.
Rooster

[Rick]

Hookup the frequency counter to R231 (100R) you may need to decouple you counter with some think like 1000pF or 1nF cap any low value cap should do, to stop you counter loading the circuit, let us know what frequency you have on channel 19 AM mode in TX also check the frequency at R232 (220R).

Can you also give us the voltages at IC9 Pins 2, 3, 4, 6, 7, 9, 10, 11 and 12.

Do give up, it is easy if you follow me and give me the info I ask for.

[rockinredsrooster]

New findings
TX frequency set to 16.2675 using vr21 (TP3-r74) set ok
LSB/TX set to10.6975 using L28 (TP6-r102) set ok
USB/TX set to 10.6925 using L27 (TP6-r102) set ok

AM/TX needs to be 10.6950 (TP-R51) Test Point 51 does not present a valid frequency. Moved L26 with no change.

[Rick]

So you did not read my last post?

[rockinredsrooster]

16.4900 @ R231
10.6970 @ R232
IC-9
Pin 2=8.02v
3=8.02v
4=22mv
6=22mv
7=3.14v
9=22mv
10=1.34v
11=1.55v
12=1.35v
Rick, I looked right over your last post. I have been at home all day snooping around this radio.

[Rick]

Well if you have check the right pins, then R230 (100R) is o/c or cold solder joint, as pin 4 should be about 8.0vdc.

I have just noted that there 2 different types for IC used as IC9, it maybe best to give me all pins voltages and the number of the IC.

[rockinredsrooster]

TDA 6130-5 Germany I will measure the remainder now. I will post when finished.

[rockinredsrooster]

#1=22mv
2=8.0v
3=8.0v
4=22mv
5=8.0v
6=22mv
7=3.15v
8=3.14mv
9=22mvv
10=1.35v
11=1.55v
12=1.35v
13=1.54v
14=22mv
pins 14&10 has a resistor copper side 1k brn blk rd

[Rick]

IC9 is OK then. Can you try your counter on the Base and Collector of TR45 and TR46 in AM mode, and let us know what frequency you have.

Do you have a RF probe or a scope?

[rockinredsrooster]

I noticed a voltage discrepancy at TR-51 Only getting 4.1v at collector on AM. But Normal voltage exist on SSB?

I do have a Tektronix 2211 scope with x10-x1 probe but I have absolutely no idea how to set it up.

I will see if my counter can-will measure those transistors. My counter has a probe connector but I doubt it's very sensitive.

[Rick]

Adjust VR13 for 5.6vdc at the collector of TR51 in the AM mode.

[rockinredsrooster]

IC9 is OK then. Can you try your counter on the Base and Collector of TR45 and TR46 in AM mode, and let us know what frequency you have.

Do you have a RF probe or a scope?

27.170mhz does exist at collector tr-45

[Rick]

Test TR45 then it may be o/c also check R220 (4R7).

[ramblingman]

hello out there..first of all,you have checked all the simple stuff first right..like the mode switch,it not got a loose wire.maybe its staying in ssb mode even when you switch to am.should be able to tell that though from your incoming rx audio.or a bad solder connection,these boards are well noted for these..also you might wanna check the rf coupling caps.i believe it is c-171 and c-175,for the single final radios..probably will be 390 or 330 pf disc caps.and also as rick told you tr-45 the pre-driver,i had a melanka with no tx symptom,turns out to be a bad tr-45 pre-driver.could also just be poor solder connection.but i dont think ic-9 gonna be the problem,i checked my schematic and the voltages you gave were o.k. there.also if you have the type of pc board,with the mirror board across tp-7 tp-8 and tp-9..sometimes if it is not making a tight connection you will lose tx.but most the time this will show up as a intermittent problem.but if i were going to guess..id say it was gonna be the old general loose connection..sometimes with these radios just being thrown together,you get the ocassional part not being completly though the pc board before it got soldered in..and then after a while it quits making connection............good luck with your radio...............ramblingman

[rockinredsrooster]

Ramblingman
Hey I went over the band switch and mode switch, both are functioning properly. I went over the entire PA section of the radio wicking up solder, scraping, reseting/soldering components. No output yet. I called the local parts store to inquire about a transistor for tr45.

The radio has a c2538 pre-driver transistor, Rick, Ramblingman, in an effort to continue troubleshooting, what's a substitute transistor I can use until my replacement arrives? I have tried crossing the part number without success.

Also, is it possible that the c1306 driver I have installed is too much for the c2538 to drive? I ordered a c2166 as well.

I appreciate all the help.
Rooster

[ramblingman]

hello rooster,,i would sure go with the 2sc2166 for the driver if it was me..also i am not sure,but i think a 2sc2086 with sub for the 2sc2538..also the 2sc2314 might sub,only thing to remember youll have to install reversed because the bias is reversed..the 2sc2538 is b-c-e- while the 2sc2314 is e-c-b-..but like i say im not 100% sure on that.you might wanna ask rick for second opinion on the subs...........ramblingman

[rockinredsrooster]

Ramblingman, Thank you.
I went ahead and ordered the proper transistors. After i get them I will post my results.

Also, Rick thank you as well.
Rooster.

[Rick]

Did you find the transistor's fault? If what was the fault they o/c or short?

[rockinredsrooster]

Rick I had forgotten about this until now, way back before you started helping me, back when this project began, a new pair of finals were installed, no change. Then a new driver was installed but the driver had the pins located on the wrong pads (installed wrong) Radio was quickly powered on then back off as a problem was obvious.
At this point, I took over and started working on the radio. I corrected the driver by installing the c1306 (new) in the correct position. I again replaced the c2312's (new) in the correct position.

So maybe this can help? I am ashamed to have forgotten about the driver c2166 being installed incorrectly. I'm not sure what chain reaction damage may have occurred?
I have not tested the pre-driver, I will do so later but for now I have some Cisco stuff to tackle. I will post my finding regarding the transistor later.