New GalaxyDX 2517 loss recieve audio

[dxswe]

Hallo

I have a brandnew galaxyDX 2517 (EPF000210Z board) 1 months old .But today I noticed that I must have full volume on the radio so I can hear my locals talking.The radio have work great until this problem is occured.Sorry for my bad English.I hope some one can help me with this problem.Even when I listening in external speaker the audio is very low,and I have also try headphones it's the same.
The IC 8 audioamp is check it seem to work correct also Q44,Q16.IC 1 the squelch circuit is still intact.

Jan from Sweden

[Rick]

Check the audio by doing a PA test, plug ext speaker in to the PA jack, switch to the MODE switch to PA, if the audio is nice and loud the AF Amp IC8 is ok. If the audio is low try replacing the AF Amp. Also check C175 and C179. Let us know how you get on.

[dxswe]

The PA seem work great I have also check the C 175,179 is also ok.The problem is between AM detector and IC 8 pin 4.When the radio is cold an newstarted the recieve audio is normal after 1 minutes is fading away.The S-meter shows right I can hear people talk all that is normal but after a minutes the recieve audio is so weak so I can't hear almost nothing at all.

Jan

[Rick]

Try disconnecting the ANF board plug J4 and insert a link between Pin 1 Purple colour wire and Pin 3 the Yellow wire, this will bypass the ANF filter board.

[dxswe]

Hallo Rick.I have try the ANF board.I bypasses that you told me but the audio i still the the same.I think the ANF boarf is intact.

Jan

[Rick]

Try putting a 10K resistor from the Yellow wire to the Orange wire on plug J5 with the volume control set to max, the audio maybe very loud.
Try un-soldering the Collector of Q44 and one leg of R221, to see if the audio is ok.

Check C38 and C97.

What voltages do you have around Q16 and Q44 with the fault?
Is the fault the same on all modes?
Do you have a AF generator? or scope?

[dxswe]

Hallo Rick.I have un-soldering the collector leg for Q44 and R221 now is the audio normal but the squelch is not working.I think we are near the problems
now.You are a great tech.Thank you Rick.Perhaps a cap is broken


Jan

[Rick]

Ok we are getting some ware then.
Re-solder R211, and check if the audio is ok?
If it is ok then re-solder the collector of Q44 and un-solder R232 and check if the audio is ok? Let us know how you get on.

[dxswe]

Hallo again Rick.Did you mean I must re-solder the leg of R221 to test if the audio is ok .

[Rick]

Sorry R221.

[dxswe]

I have re-solder the leg of R221 the audio i working but I haven't re-solder the leg of Q44 yet.

[dxswe]

Hallo.
I have re-solder the leg of Q44 and audio disapear but when I un-solder the leg of R232 the audio is normal again.
Jan

[Rick]

What is the voltage on Pin 8 of IC1 with the squelch at max and min?

[dxswe]

At min 0,32 V and max 7,32V

[Rick]

Re-solder R232, and check the voltage at the Base of Q44 with the squelch at max and min?

[dxswe]

At min 0,63V at max 0,73V

[Rick]

Try replacing Q44 as it look like it has a Base to Emitter leak.

[dxswe]

I check the voltage for IC 1 pin 8 min 0,67V and max 7,10V.

[dxswe]

Ok I should replace Q44 2Sc945.Very many thanks.

[dxswe]

Hallo again Rick.I have replaced Q44 but the audio is still weak.But if I un-solder collector of Q44 the audio is strong and normal

Jan

[Rick]

Ok then, re-solder the collector of Q44 and let us know what the voltage is each side of R232 withe the squelch at Max and Min?

Also check D37, D69 and C80 maybe faulty.

[dxswe]

I have the voltage for R232 to Q44 is min 0,63V and max 0,74V and the other results for R232 is min 0,8V max 3,92.I have also check C80 is still intact.

Jan

[dxswe]

I have also check C189 it seem to be intact.

[Rick]

The problem is that Q44 is being turn on, the Base voltage should be about 0.2 VDC or less with the squelch at Min and about 0.8 VDC with the squelch at Max.

If the voltage at IC1 pin 8 are has you have told me is At min 0,32 V and max 7,32V, then that is ok. so where are the volts coming from?

Have you check the diodes D37 and D69?
What is the voltage at each side of R63 withe the squelch at Max and Min?

[dxswe]

Sorry didn't you mean R62 instead of R63

[dxswe]

D37 D69 is intact

[dxswe]

The base Voltage for Q44 is at min 0,63V at max 0,72V.So the voltage is to high for base at min I have 0,63 it sholud be 0,2 its that correct.


Jan

[dxswe]

Hallo again Rick.I have check the voltage for R62 to IC 1 Pin8 min 0,62V and max 7,07V.I have also check the voltage for R62 to D37 min 0,83V max 3,91V.



Jan

[Rick]

Ok then, if you have more volts at the junction of R62 and D37 then the volts must be get in at D37 or D69, try un-soldering one end of D37 and D69. if this works then check the voltage at D37 and D69.

Also try un-soldering one end of R62.

[dxswe]

Hallo Rick. I will try yours suggestion tomorrow.
Best regards Jan

[dxswe]

Hallo Rick.I have un-solder one leg of D69 and now the audio is working normal also the squelch is working.Everything seem to work normal,can I have the leg of D69 un-solder or is that not good.What have D69 for function?


Jan

[Rick]

Re-solder D69.
Try the following and let us know which one cures the fault.
Before moving on to the next stage re-solders the component
1. Un-solder one leg R228, do you still have the fault?
2. Un-solder and remove Q60, do you still have the fault?
3. Un-solder one leg D150, do you still have the fault?

[dxswe]

I have check the voltage for D69 the leg whois un-solder to R62 is at min 0,0V and max 0,10V.


Jan

[dxswe]

Hallo Rick.When I have un-solder the leg of D150 the audio and squelch working normal.I have also try Q60 R228 but then the audio is weak.


Jan

[Rick]

It looks like D150 is leaking, try replacing D150.

[dxswe]

Ok I will replaced it.Thanks again


Jan

[dxswe]

Hallo Rick.I have replaced D150 it seem to be the faulty.Now is audio working
perfect .I will thank you for your time to solved this problem many many thanks.I owe you are beer.


Jan

[Rick]

That good news, now you are up and running again.