| Author |
Message |
    
Vanillagorilla
Advanced Member
Username: Vanillagorilla
Post Number: 700
Registered: 4-2005
| | Posted on Monday, July 31, 2006 - 2:58 pm: | 
|
I have a friends Galaxy 33HML stting in front of me thats having a sort of "self ossolation(sp?)" problem since he did the ERF2030 dual final mod.
Heres how it goes. Key the mic and modulate fine. Unkey the mic and its still SORT of stays keyed but with no modulation and no freq displayed on my external meter. No signal seen on another side by side radios RX either.
The radios RF meter as well as my inline meter show a jump in output wattage when unkeyed?
NOW...if you flip the echo switch OR power the radio on/off it will resume RX until the next key up.
Only thing I've been able to conclude is the EN-369FN that is soldered on the PCB side of one of the final 2030's is a bit of a mess (solder glob) If I short the Gate side of the tranisistor where the "+" side of the EN-369FN goes it works but with an ULTRA low DK swinging less than it should.
This done ...the radio will TX and RX as normally expected but with low output. Is it possible one of the componants is bad? He added the second 2030 as per instructions but I see NO isolator between it and the chassis either?
I guess what I'm trying to find out is the actual purpose of the EN369FN? Seems like something wants to be drained of RF....something is keeping some sort of RF inside the radio.
I did this through my antenna system and a dummy load as to cross off the possibility of reflected power holding it.
This radio ALSO has the voice recorder toy. Noticed that when this GALAXY is doing its funny thing..if you just barely touch the record button it also drains(?) the radio into dropping the signal and resuming RX.
Not quite sure I'm making ANY sense here  probably confused anyone reading more than helped myself. Let this be an indication of how much this thing is driving me nuts!
Oh by the way...its been to a "tech" as well.
It might be of some help to say that this radio AFTER the conversion worked in my friends base BUT not his mobile. I saw this radio "key and unkey" at the tech shop after its second trip. I got it home and wanted to test output before sending it back to SOUTH CAROLINA! Thats when I saw the problem repeat itself for the third time!
Thanks for any help!
BTW...BRIAN! If your reading this please forward me the name of a good tech in SC!
Hank |
Bc910
Advanced Member
Username: Bc910
Post Number: 752
Registered: 7-2004
| | Posted on Monday, July 31, 2006 - 3:45 pm: |
|
Ground problem possibly?
Thats my guess
BC |
Vanillagorilla
Advanced Member
Username: Vanillagorilla
Post Number: 701
Registered: 4-2005
| | Posted on Monday, July 31, 2006 - 4:15 pm: |
|
Update!
We have no futher FORWARD progress as the radio JUST decided to shut off! I suppose its needs a rest now?!
Had it turned on sitting while I did other things. Was receiving fine just sitting THERE with covers on but not screwed down!
Then I hear my power supply shut off...hmmmm.
Go over and check things out. Looks like SOMETHING shorted. Checking between the pos/neg I show short or "0" ohm. Disconnect reverse polarity diode and short still present. WHAT ELSE could have shorted just sitting? I see nothing burnt or shorted from known power or ground of any kind.
Its got too many toys as it is but all looks secure and isolated.
Hey Pat? Remember where you threw that Galaxy out a window? I may need parts!
AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH!!!! |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 1927
Registered: 9-2004
| | Posted on Monday, July 31, 2006 - 5:18 pm: |
|
if that chassis is the same one im thinking of, then TR41 is a 2SA473, and TR51 is a 2SB754.
if thats the case, then you might suspect TR41 as its the voltage regulator, and might be shorted.
this might have happened because the 2SB754 which is the AM modulator, couldnt handle the increased swing after the mod.
this could be why the TX was "hanging up".
if you are going to replace them; upgrade them.
i will do some checking and give you the upgrades, and maybe other stuff.
check back soon.
matt |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 1928
Registered: 9-2004
| | Posted on Monday, July 31, 2006 - 5:32 pm: |
|
ok, first off, look over the ERF mod in this link, and make sure you/he did everything the right way.
the insulator MUST be used.
also, i noticed that they mention NOT to bend the leads of the EN369 too much, or aggressively, as it could be damaged. (this part is a diode and one other part put into one package, and it is used to get the right impedance for the input of the MOSFET. they want very high input impedances)
here is the link to make it easy:
http://www.copperelectronics.com/cgi-bin/discus4/show.cgi?tpc=7750&post=114769#POST114769
more to come, check back soon,
matt |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 1929
Registered: 9-2004
| | Posted on Monday, July 31, 2006 - 5:59 pm: |
|
ok,
if you find this to be the problem;
replace TR51 with 2SB817 (much better part,12a as opposed to 6a)
replace TR50 and TR41 with 2SA1012's.
also, if you're thinking about replacing the ERF2030's, remember that you can get an EXACT sub for much cheaper. its the IRF520. only about 2.00.
good luck, if i find out how to make your own EN369 part, i'll post it.
matt |
Vanillagorilla
Advanced Member
Username: Vanillagorilla
Post Number: 702
Registered: 4-2005
| | Posted on Monday, July 31, 2006 - 6:56 pm: |
|
Thanks KV...those look like the instructions he sent with the radio. I went over them pretty good. Thanks for all the other info! I'll look into all that as well. Good stuff.
If I could find those parts around here I'll do it. If I have to order them then it goes back to the owner and he'll do it. I'd just like to help out and learn at the same time...where possible.
Hey BC...funny you speak of ground isssues. I'm NO tech BUT shouldn't the "common foil"..you know the BIGGEST one that runs across the rear of the radio have continuity to chassis ground? And for that matter shouldn't the neg post on the power input ALSO have continuity to chassis ground and common foil?
Because as of right now...THEY DON'T!
Oh I feel a migrain... |
Vanillagorilla
Advanced Member
Username: Vanillagorilla
Post Number: 703
Registered: 4-2005
| | Posted on Monday, July 31, 2006 - 7:02 pm: |
|
Oh btw..as for the shut down issue (that I have yet to look at...)
Its NOT blowing the POS 2A fuse...but shutting down the power supply instead. If I short the radio it SHOULD blow a fuse. Now I need to think
Stupid question...wonder if I installed a fuse in the NEG line and THAT one blew?
Would that give me something to go on as far as bringing it back to life?
SO WE CAN REPAIR THE ORIGINAL PROBLEM! |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 1933
Registered: 9-2004
| | Posted on Monday, July 31, 2006 - 8:57 pm: |
|
makre sure you have the power wires unhooked from the power supply when testing for continuity between the pos and neg.
also, there is NO continuity between the chassis (metal) ground and the PC board ground.
they are only connected with disc caps which means there will be NO DC continuity.
so the radio is OK in that respect.
try removing TR41 and testing it in your voltmeter if it has HFE. the 2SA473 is a PNP transistor and the NTE equivilent is the NTE153.
the NTE sub for the 2SB817 is the NTE37.
good luck,
matt |
Vanillagorilla
Advanced Member
Username: Vanillagorilla
Post Number: 706
Registered: 4-2005
| | Posted on Tuesday, August 01, 2006 - 9:15 am: |
|
Hey Matt...I sent my last message before your last one...with the quotes... appeared.
This last quote:
" Try adding a 3000 Ohm reisistor between the gate and source . That would be the two outer legs on the device. The gate is staying open, and a small negative voltage will close it. The acessory diode should prevent this occurence but for some reason it isn't."
..kinda hits the nail on the head! All other info invalueable and has me thinking that I'm looking in the right direction. All I have to do now is get it to power back up!
When checking the continuity between the pos/neg I did it from outside the radio...power unplugged. Once it shut off my power supply It was disconnected to prevent further damage. Still curious why it shut off the supply and didn't blow the fuse that I'm certain is 2A.
I'm now trying to find the source of the short. Its not the reverse pol diode...and why would it be.It worked for a while before saying goodbye.
I have some extra initial testing to do THEN on to your advice above. Thanks a million for your input..TechVicious.
Hank |
Vanillagorilla
Advanced Member
Username: Vanillagorilla
Post Number: 719
Registered: 4-2005
| | Posted on Thursday, August 03, 2006 - 6:59 am: |
|
I know exactly what you mean on all accounts
Well then I'll keep you updated! Still need the time to get back into that radio..BUT I WILL BE BACK!
Hank |
Vanillagorilla
Advanced Member
Username: Vanillagorilla
Post Number: 818
Registered: 4-2005
| | Posted on Sunday, September 10, 2006 - 10:17 am: |
|
Quick BTT for future search users looking for an answer. EKL 2030 finals replaced with 2SC1969's...problems solved. Will swing 40+ from whichever deadkey set with HML switch.
Still using 2030 as driver.
Thanks KV for your time!
Now....
GET THIS OUT OF MY SHACK!
Hank CEFF559 |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2061
Registered: 9-2004
| | Posted on Monday, September 11, 2006 - 10:54 pm: |
|
good deal hank!
glad you got it working. what a great feeling eh?
guess the ERF2030 just had too much gain.
if you MUST get rid of it now; just mail it to me along with a money order for 35.00 for my troubles.LOL
matt |
