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Direct injected galaxy DX55V wattage problems

Ok, that buzz is from the difference in potentials - you do have a ground current running thru, and both power supplies are trying to handle that "ripple".

So, line isolation is needed.

I too own a Dell that uses single port - so I know there are power currents that flow thru the tip, sleeve and shield points on the connector.

I cannot connect the Dell to anything else without Windows attempting to communicate via those currents the ports "sense" thru this jack. So - I have to remove any power supply that can generate a cross-feed problem - so the device it connects to - needs to be under BATTERY power for itself and it will use the Shield (bottom contact - or last contact) on the sleeve to shield and reference - this is where those currents show up.

So caps to isolate all - and a dropping resistor of about 600 ohms from Sleeve to Shield and 1.5K resistor from TIP to shield - on THE PC side (no not radio - radio remains isolated thru CAP isolation on all contact points)

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This is part of the problems with laptops and multimedia-based entertainment systems. Their ability to incorporate a floating ground point using single port - multi function interfaces.

So more than likely it's shooting a low -power current out looking for something to return back to it to tell it what to do. But, as a stand alone - it appears to itself as a high impedance "loop" between the tip, sleeve and shield points to allow the audio in, out and MIC functions like you'd have with a typical stereo headphone media for smartphones (earbuds - built in MIC with Call back, and Audio playback control features) thru a push-button switch.
 
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One of my problems I have is I can't isolate board ground from chassis ground (radio side). My shielded wire in the radio for DI is going to L5 board ground and the metal on the headphone port I installed has ground/shield on the radio I have touching chassis ground with no insulation in between. But even removing the inlet does the same thing while plugged in. I can fix my buddys computer to make it stop messing radios up, I just can't figure out the radios problem now. Something was done to it when hooked up to his computer, the radio still does the same on my computer so theres something blown in the radio itself. Thanks for the info Andy and sp5it
 
More than likely the Inject point - that cap may have become leaky.

This is where the caution came in - when it comes to radios chassis ground versus PC's "apparent" ground - can be two different levels - and like nature abhors a vacuum, the Electrons look to find holes where they can, so a trickle current flows, but can have some voltage to it - like static.

This then turns into the realm of ripple when the line voltages are isolated thru double insulated and wall warts, but there is the effort of the ground the radio has, to the ground the PC has, are two different levels.

Was the PC and your radio connected to the same wall outlets?

Was his antenna also grounded at the exterior, at the antenna? This may have been that "difference" that popped a cap because of the exceeded voltage ratings if only for a moment.

You did say you had a hum - so the length of time that hum took place, the damage may have been done was during this noise loop you encountered.
 
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His antenna is grounded at the base with a ground rod, radio is hooked to a 72 amp power supply on the same wall the computer is. The difference in his setup and mine is I run solar and battery on all my equipment with charge controllers limiting the voltage from over charging, but I run my equipment other then the laptop off battery power. Laptop is plugged into a wall outlet. I talked with him just a little bit ago he wants to try to use the same computer if he can if we get the 55 going right lol, Are all the outputs for audio on the computer using the same ground? There are several audio outlets for headphone plugs on the back for speakers that can be used for audio from and to, I'd just have to go into the sound setup and change the output if the grounds were seperate? I know it's still not isolating the ground though. I'm just guessing at this point. Thanks for the info Handy Andy
 
That_guy_in_wv said:
His antenna is grounded at the base with a ground rod, radio is hooked to a 72 amp power supply on the same wall the computer is. ...[...]... Are all the outputs for audio on the computer using the same ground? There are several audio outlets for headphone plugs on the back for speakers that can be used for audio from and to, I'd just have to go into the sound setup and change the output if the grounds were seperate? I know it's still not isolating the ground though. I'm just guessing at this point. Thanks for the info Handy Andy
Click to expand...

Good to know he grounded his equipment but that also shows how this happened - static ...thanks this helps remove some other problems - but you still have a leaky cap on your radio at the injection point.

Actually, they (Windows or Linux or Other OS) - simply will route audio automatically. So the "ground" should be the PC's chassis for RFI/EMI shielding - but not always the truth, you'll need to double check the case to USB metal support frame any one should all be the same- to verify the case and chassis are the same.
 
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I changed c191 with another new 10UF 35v capacitor it's still the same, that was the first thing I tried. If I follow the circuit it leads to a resistor that goes into the audio amps and regulators through a few caps I've changed already, I might have to go in deeper onto the line that leads from the audio input from c191 and see what happens if a few caps are swapped out. Audio amps and regulators are showing good voltage but the pre driver tr46 still has high voltage on the collector coming from the audio amp side.
 
Other then changing a few ceramic disc capacitors I still have the same problem. Should I start on changing caps leading from board ground to case in the radio?
 
The Disc's wouldn't be the problem - directly.

Here's what I see -- Direct inject, unless you make a breakpoint, the "line" you tap into, The parts in the chain - both ahead of, and behind, that point - are "seeing" this ground current.

This may be more than a cap - I wish I could simply say, yes - change Cxx to this and you're fine, but - each injection "radio" I've had to rebuild back to stock, has always - ALWAYS - had problems both behind back at the output stage of the PREVIOUS section, and the INPUT to the next section.

Even Mic amp - the Rheostat (Pot) and any Echo boards - easier to trash the cards as this occurs and start anew than to chase down SMD parts that may or may not be leaky, only "questionable" because of the jolt to the system.

Each Inject User, places their components is different locations - nothing is truly standardized - else I'd be able to point you to the spots you need to check.

But this kind of "damage" comes at the price of the inject - if no break in the circuit was provided, all the loop of parts in the chain, ahead of and back behind are all suspect.

I'd need to know where you placed your inject point at so I can even locate a point to begin...
 
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C191 is where I inject audio, the hole closest to the center of the radio is the positive of the 10uf cap the negative side of the cap goes to audio (center pin) (tip) on the audio cord from the laptop. I was wondering if it could be a component behind the inject point but didn't ask cause I didn't figure it would have mattered where it wasn't being used after c191.
 
I'm looking at the 33HML - but similarly - I think you may have the "same problem" just different radios so it may be the same way to track this down...

Locate VR13 - make sure the POT is not OPEN on the substrate...Same for VR16 trim for - and including - RF power - it may have opened.

Check all leads of the pots, from 8 V positive side, across to ground is it 5K? If not the pot opened up - replace the pot...

The HML uses 3 different VR's to handle Hi, Mid and LOW - 2 to handle the AMC limiters range of control - so you need to do the same thing for them.
On the 55' - similar Only RF power pot VR16 and RF Power but then again apply to see if 8V is adjustable at TR51 at the TP's is an easy check.

IF the pots are ok, the only way the wattage goes up and stays up is from the AM regulator taking a hit, anything from the D91 Bypass cap onto TR50 and TR51 - especially if audio is getting crappy...more than likely it is from a leaky transistor - but so save time and effort later - replace C190 - if you use 220uF - go back to 100uF until we get audio stabilized.
 
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Handy Andy said:
I'm looking at the 33HML - but similarly - I think you may have the "same problem" just different radios so it may be the same way to tack this down...

Locate VR13 - make sure the POT is not OPEN on the substrate...Same for VR16 trim for - and including - RF power - it may have opened.

Check all leads of the pots, from 8 V positive side, across to ground is it 5K? If not the pot opened up - replace the pot...

The HML uses 3 different VR's to handle Hi, Mid and LOW - 2 to handle the AMC limiters range of control - so you need to do the same thing for them.
On the 55' - similar Only RF power pot VR16 and RF Power but then again apply to see if 8V is adjustable at TR51 at the TP's is an easy check.

IF the pots are ok, the only way the wattage goes up and stays up is from the AM regulator taking a hit, anything from the D91 Bypass cap onto TR50 and TR51 - especially if audio is getting crappy...more than likely it is from a leaky transistor - but so save time and effort later - replace C190 - if you use 220uF - go back to 100uF until we get audio stabilized.
Click to expand...

Thanks andy, I have a 330uf in c190 I'll switch it back to the 100uf and check all the points you spoke of. I just needed a spot to start also the caps I have changed so far (electrolytic) I've found a few leaking. I like throwing new parts into radios but I'd rather find the problem then change components that don't need it.

Again thank you andy, I'll reply the results I find tonight if I get time, i been busy getting my place ready for winter at the moment.
 
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