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Bigbob
Senior Member
Username: Bigbob
Post Number: 2223
Registered: 12-2001
| | Posted on Saturday, October 01, 2005 - 8:29 pm: | 
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Why does the eagle 2000 require only 20 milliamps at the driver,while the dx2517 requires 50-75 milliamps,quite a variable on the dx,50-75 +/-5 milliamps,is it 50 or 75 or anywhere in between,now the eagle gets 14 volts at the driver and final on ssb,while the dx gets 13.3 volts,well we all know when you reduce voltage you must increase amperage to achieve comparable wattage,but it seems 50-75 milliamps is a little excessive,what do you all think?Bigbob |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 1582
Registered: 7-2004
| | Posted on Sunday, October 02, 2005 - 10:12 pm: |
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for BOTH the EPT-3600(eagle 2000) & the EPT-6900(DX2517):
DRIVER BIAS: Connect DC Ammeter between TP9 and TP8. Key TX, adjust VR11(for 3600 or VR12 for 6900) for 50 Ma.
FINAL BIAS: Connect DC Ammeter between TP9 and TP7.
for 3600:for single final models key TX & adjust VR10 for 100 mA. for dual final models , first key TX & adjust VR10 & VR20 for mininmum(zero) mA current. Next adjust VR10 for 50 mA, then adjust VR20 for 100 mA total.
for 6900:Key TX & adjust VR10 & VR11 for minimum(zero) mA current. Next adjust VR10 for 50 mA, then adjust VR11 for 100 mA total.
75 mA, + another 5mA? 80 mA at that poor little driver? sure way to get the radio to scream, & some sales at the ole transistor dealer...
where'd you see 20mA, bigbob? you been wearing BC's glasses? |
Bigbob
Senior Member
Username: Bigbob
Post Number: 2228
Registered: 12-2001
| | Posted on Monday, October 03, 2005 - 3:56 am: |
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Well actually I made a mistake,the 20 milliamps came from an old service manual that I got from copper for the galaxy saturn when nobody had any alignment info By the way,could you run the driver at the higher setting if heatsink were backed up by a finned heatsink and a fan?Bigbob |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 1594
Registered: 7-2004
| | Posted on Monday, October 03, 2005 - 10:33 am: |
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interesting thought...go to rf parts, or somewhere, to get specs on BOTH drivers & finals & see what they will handle. the more amps/volts to any of them, then the more heat removal will be needed. also, at some point, you may get back to power supply issues. |
Bigbob
Senior Member
Username: Bigbob
Post Number: 2233
Registered: 12-2001
| | Posted on Tuesday, October 04, 2005 - 6:58 pm: |
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Yeah mainly the dumb old 2sb754,ya know it really stinks that instead of replacing the regulator with a heavier unit they come up with this convoluted way of reducing the voltage to the final and driver to protect the regulator what a bunch of cheap skates,what is the regulator in the S-9?I bet it's not the puny 2sb754.I'm looking at possibly drilling the heat sink to take a TO-3 mj2955 15 amp transistor it's a switching power transistor of the PNP type,but need some way of getting the full 14 volts to the rf section on ssb,current system allows only 13.29 on tx,I think adding some resistance to the ssb rf power pot may work,as I did this to the rf power front pot(1.5k)and gained a watt,I removed it back to stock and will try this on the ssb pot,I'm only looking for.7 volts,heck maybe a 1n914 on the ground side to raise it's potential .7 volts,hmmm,not sure what to do but anyhow wife said if I mess this radio up it's the last,sigh.Bigbob |
Bigbob
Senior Member
Username: Bigbob
Post Number: 2235
Registered: 12-2001
| | Posted on Sunday, October 09, 2005 - 2:22 pm: |
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Are all the techs on vacation?Another question,can I paralell the transformer from my eagle 2000 with the transformer of my dx2517 before the rectifier or do I need to run two rectifiers and paralell after and what do you think of hard wiring the 2 finals and driver from the eagle to the finals and driver of the dx2517 in paralell and heat sinking them as well,then with the mj2955 in place of the 2sb754 I think power supply would be stout enough.Kind of a frankenstein don't you think?OR how do I get more voltage from the 2sb754 to the driver and final without having to volt anything unless that will work as I NEVER talk on A.M.,I'm only looking for 14 volts and the 15 amp regulator is a sure thing,just got to remember to blow out the drill shavings before firing her up. I know Pat00 is tired of dealing with me,I just thought there was more techs than Lon who could help,nothing wrong with Lon but he can't possibly answer every question from everybody and I don't expect an answer from him all the time,I mean he's got a life too,just like Pat and everyone else in here.I guess some radios aren't worth reengineering but those that are don't need any,a catch-22.Well I 'll cease my boring drivvel.Bigbob |
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 1641
Registered: 7-2004
| | Posted on Sunday, October 09, 2005 - 7:23 pm: |
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 !!!
actually, i like some of your questions, bigbob! they make me think-have i or have i NOT tried them before, and, then i realize why i stopped trying to get EVERY LAST OUNCE of audio or wattage out of something! nowadays, i just stick mostly with basic mods, then go 'bigger amp', & am done with it! have a TR296 on the bench with a 2290 added to it that worked fine when i fixed the hack job, but now it won't xmit again, and another i just did that gets SMOKIN' HOT & only is keying 10 watts & swinging 50...just don't have time til winter gets here. then, i heard a 101e last week, so decided to open mine up & see what's up with it...probably should send it out, but $30 each way...
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