Would like to still find the damage done, but would also like to re-locate the DI location to a different ground or different place on the board even if I had to, weird though that it didn't do the same to my other 55vdi that works fine but you know radios are weird sometimes. I'm not sure what power choke your speaking of unless you mean the chokes coming in from the 12v power plug on the back, I've tried running the ground to case from the audio and it has to be board ground to not squeal but I wondered if being shorted to case ground from that audio plug had something to do with it, board ground was the only way to nake it not squeal. How would I "carefully" go about changing grounds from the shielded cable I have at L5 to the power choke? Again thank you handy Andy I think we're getting closer and closer to finding the problem with this. I'll go through the circuit at L5 and check the voltages at ic1 and ic2 and change L5 just to be sure, might even change ic1 and ic2 while I'm in there if voltages are off, I should have the spare parts here somewhere. I'll try to get it done tonight when I get back home.
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Direct injected galaxy DX55V wattage problems
- Thread starter That_guy_in_wv
- Start date
I checked the voltages on ic1, ic2 and ic6 and replaced L5, voltages were fine other then 2 of the pins squealed back through and had the modulation and wattage pegged checking in tx mode on ic6 mic amp think it was showing 4.50 volts on both pins still though so voltage was good.
before I took out the DI mod I checked it again to see if that had fixed the problem and ran the ground from the audio cord to the ground choke, now no matter where I put the ground now the wattage pegs out to 26-28 watts drifting down the longer the key is held even if it was back just touching L5, same thing the 33hml does so whatever went out I guess went completely out, took out the di mod and returned the radio to stock and works fine on AM/FM modes no problem, so it's only when direct injecting at c191 when the problem happens again.
before I took out the DI mod I checked it again to see if that had fixed the problem and ran the ground from the audio cord to the ground choke, now no matter where I put the ground now the wattage pegs out to 26-28 watts drifting down the longer the key is held even if it was back just touching L5, same thing the 33hml does so whatever went out I guess went completely out, took out the di mod and returned the radio to stock and works fine on AM/FM modes no problem, so it's only when direct injecting at c191 when the problem happens again.
Ok so I ran out of ideas and just went testing different spot in the radio and found that the hots on the external speaker and PA speaker have 5.6 volts on them, I thought it was kinda weird because there shouldn't be 5 volts on them, my 66v shows 0.0vdc when testing all points on the pa/external speaker on the board. Thought maybe that info might help us get closer to finding the problem also
Interesting to find a voltage on them...
How is the speaker, Audio Caps and the route to the jacks...
To see 5.6 volts indicates a shorted cap - it's 1/2 the supply voltages used at the Audio Chip
The 5.6 volts - can also push several amps so don't cause too many shorts, else it will open a trace (or several)
How is the speaker, Audio Caps and the route to the jacks...
To see 5.6 volts indicates a shorted cap - it's 1/2 the supply voltages used at the Audio Chip
The 5.6 volts - can also push several amps so don't cause too many shorts, else it will open a trace (or several)
Exactly what I'm talking about...Common sourcing ground.
There are grounding jumpers you can use too...
But here's why I'm concerned...
IC 2/L5 Leads are highlited, Orange and Amber
RED refers to a power feed/signal.
NOTE HOW L5 STRADDLES this!
Those ground traces are pretty tiny....
I hope this graphic helps because you may have to look for an open trace in the ground foil
There are grounding jumpers you can use too...
But here's why I'm concerned...
IC 2/L5 Leads are highlited, Orange and Amber
RED refers to a power feed/signal.
NOTE HOW L5 STRADDLES this!
Those ground traces are pretty tiny....
I hope this graphic helps because you may have to look for an open trace in the ground foil
I'll look around and check some more caps and those traces from and around L5 and check the caps to, from, and around the ex/pa plugs. I'll get back with you thank you for the help handy Andy.
C145 is the main Audio output cap, so to see that pushing over 5 volts - whoa!
Got a Grain of Wheat lamp (meter light)?
Might want to "test" the 5.6V short...at the SP jack
Strong current thru the lamp will light it but not damage the foil traces.
A "phantom" 5.6 volts shows leaky - else lighted lamp means serious failure.
Got a Grain of Wheat lamp (meter light)?
Might want to "test" the 5.6V short...at the SP jack
Strong current thru the lamp will light it but not damage the foil traces.
A "phantom" 5.6 volts shows leaky - else lighted lamp means serious failure.
C145 is where I traced the voltage back to, getting ready to check with a light to see. I'll get back with you Andy, thanks.
Won't light up a wheat lamp if I'm doing it right, but an led meter light shows some light when touched to the contact's.
Means the cap is leaky - swap it for another fresh...
If the caps internal resistance was really heading south, the next step it would take is - as it tries to to push power thru itself - as a dead short.
It's a good example of how caps fail over time, or aged caps or even marginally pushed over the edge caps work. They gas a bit, then the plates go dry, and eventually - you don't have a cap - but a low-values resistor with a lot of fun-fetti' foil ready to pop.
Always willing to help...
SIGH...
If the caps internal resistance was really heading south, the next step it would take is - as it tries to to push power thru itself - as a dead short.
It's a good example of how caps fail over time, or aged caps or even marginally pushed over the edge caps work. They gas a bit, then the plates go dry, and eventually - you don't have a cap - but a low-values resistor with a lot of fun-fetti' foil ready to pop.
Thanks. I forgot to order grain of wheat lamps.
Always willing to help...
SIGH...
Means the cap is leaky - swap it for another fresh...
If the caps internal resistance was really heading south, the next step it would take is - as it tries to to push power thru itself - as a dead short.
It's a good example of how caps fail over time, or aged caps or even marginally pushed over the edge caps work. They gas a bit, then the plates go dry, and eventually - you don't have a cap - but a low-values resistor with a lot of fun-fetti' foil ready to pop.
Always willing to help...
SIGH...
I didn't realize who mentioned the lamps first. I ordered the stuff to roll a plate choke and need a lamp to test it. The mag wire is here the hdpe rod is to be delivered before 9 and the lamps are coming tomorrow.
Replaced c145 with a 330uf 25volt and still have around 6volts coming from the audio chip side going to the hots (centers) of the ex/pa speaker contacts, not sure what's going on here. I've replaced all parts on the board going to that foil that the Audi chip is soldered to, still doesn't make sense, unless the audio chip is blown or shorted somehow? But it's always had 6 volts there and is supposed to but not past the cap at C145, every cap I replace has voltage going across the jumper at j3 in front of tr52 and into the ex/pa line at the rear on both hots. There's only C148, R202 and C146 connected on the same pad as C145. R202 leads over into R203 and from there over into d80 and into C150, the unbanded side of d80 goes over to Tr30, sorry I couldn't figure out how to share a circuit diagram I highlighted lol. Could this be the short that keeps blowing the caps at C145? Even though I changed tr30 at the beginning. Sorry took so long been busy, and thanks for staying with me on this y'all.
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