| Author |
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d104 Ohio
| | Posted on Friday, August 02, 2002 - 9:44 pm: | 
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I saw something at a CB shop called an internal stinger board, basically it's a 50-75 watt internal linear. I was just wondering how much power the transformer in the Melaka can stand or if I'd have to replace it? I noticed that the stinger board at a maximum draw only takes 4 amps total at 13.8 volts dc. If I were to install it I would turn the stock power down to less than 10 watts PEP so it will run the board better, but would this provide enough breathing room for me to install the Stinger? I don't have an echo board or any other power drawing devices installed. Would this mod work without upgrading the power supply? If not, what should I replace it with and where can I get it? |
Taz
| | Posted on Saturday, August 03, 2002 - 10:11 am: |
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Good question, I put one in a cobra 29 once! man was it loud! |
307
| | Posted on Saturday, August 03, 2002 - 6:40 pm: |
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By the time you spend the money for the "toy" and spend the money for the "installation" , you are at the cost of a 300 watt amp that will far out perform the little internal "toy"...Plus they create all kinds of problems. Internal squealing , Power Supply slamming , feedback and a bunch more...
307 |
Taz
| | Posted on Saturday, August 03, 2002 - 9:06 pm: |
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power supply slamming? |
d104 Ohio
| | Posted on Saturday, August 03, 2002 - 10:55 pm: |
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I didn't ask for an opinion, I asked for tips on how to do it. I got the Stiger Board for free actually, I got a 12-14 AMP transformer sitting here that was give to me also... so actually it cost me nothing but the work, and thats what I like to do, the work. Thats the fun part to radios for me, experimenting. On the matter of a linear, I got a good 600 watt linear right here. I just wanted something to DO, just wondered if it's possible and tips on HOW TO do it. Thank you. |
Jimbob
| | Posted on Sunday, August 04, 2002 - 12:03 am: |
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4 amps rating seems low for quality class B or better class AB2 amplifier operation. Anyways, you should replace the power supply transformer with a larger unit. The pass transistor better not be a lowly 2N3055 either. This is a job for a technician. Proper shielding should stop 'RF in the audio' problems. Sounds like a cool project. About one 'S' unit difference on the receive end of your signal comparing 75 to 300 watt output. |
d104 Ohio
| | Posted on Sunday, August 04, 2002 - 2:52 pm: |
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Yeah, I got a 12 - 14 amp transformer here, I think the pass transitor is has an 2SB847 in it, I believe, I'll have to check it out later, I just wanted a project to do! lol. Actually, since my first post... I did add a turbo echo board. I wish there was a place to buy the knobs like on a DX2517... that way I could put the dual echo knob in the front in place of the TONE control and not have it hick chrome, jk. And I'd also like to make the RF GAIN the RF POWER instead (or another dual knob to be both RF gain and power)... have all my extra controls infront. Also I noticed something about the Melaka, it doesn't have a noise blanker... when I tried to add a fan(s) the received whined horribly... Even though the fans are 12 volts (and 0.29 amps) I put a small 6.3 volt 12 amp Rad Shack transformer in there for the fans, tied it into the 120 on the fuse in the back... it works perfectly... the fans aren't top speed of course... but the transformer runs very cool, and the fans being a bit under par makes them quiter. One of the techs will probably respond to all this later with I'm wasting money... I got the Melaka in a trade, the 14 amp transformer for free from a local tech, got the stinger board for free (it was thrown in during a trade because the guy didn't know what it was actually, never even opened it), the only thing I actually paid for was the echo board, got it for $15.00 on eBay new. So as for money, I've only for $15.00 in it so far. And if you're thinking about the fans and transformer, free also... just put them on there because the final has been volted...gets a little warm when I talk for a while on AM.
I love projects! |
Taz
| | Posted on Sunday, August 04, 2002 - 5:07 pm: |
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I put a fan in my melaka and it runs cool as heck! Ive done hour long keydowns and still cool.
so far I have
Added a 10kc switch
Unlocked Clarifer
Variable Power
Added Fan
Next is an echo board and then a rodgerbeep.
What else can I do to it? |
d104 Ohio
| | Posted on Sunday, August 04, 2002 - 7:39 pm: |
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I got 2 fans, a variable power in the back, unlocked clarifier, 10 kc switch, a switch to restore the 10 meter voice band... the TRB-1 Turbo Echo Board... in my last post, I was talking about moving the variable power and echo tone to the front...it gets to be a hassle reaching behind the radio all the time. What I was asking 307... I was gonna upgrade the transformer and add an internal linear / modulator... I don't know how much more you can add though without upgrading the power supply... one of the Melaka's I had in the past, after adding the echo board and a 5 tone roger beep, volted finals... the works, but my swing dropped from 28 to 21... and on some channels I had a feedback.... one I removed the echo... it went to 25 watts again... the transformer isn't as strong as it seems! But if you upgrade the transformer... the possibilties are endless really... just isn't worth it though if you have to pay someone else to do it. You could buy a Dx2517 instead. But if you're like me and wait for everything (get it cheaply), then you have a DX2517 without a counter for half the price! |
Taz
| | Posted on Sunday, August 04, 2002 - 10:37 pm: |
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2 fans? man where did you put them? |
Taz
| | Posted on Sunday, August 04, 2002 - 10:46 pm: |
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thats my goal!
Hey d104 after I add the rogerbeep and an echo board will I lose any power? |
Taz
| | Posted on Sunday, August 04, 2002 - 10:48 pm: |
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hey did you say you got that echoboard off of ebay? |
Bigbob
| | Posted on Sunday, August 04, 2002 - 11:26 pm: |
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Is there enough room to run 2 transformers in parallel,that other transformer must be shielded completely or you get 60 hertz hum. |
Taz
| | Posted on Monday, August 05, 2002 - 12:44 am: |
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no there isnt enough room. But I suppose it could be external |
d104 Ohio
| | Posted on Monday, August 05, 2002 - 1:07 am: |
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There is plenty of room, the transformer I added for the fans is tiny... put in front of the stock one.... and I don't get any hum from it at all... besides...there were empty holes for me to mount it! And how come everyone is talking about shielding... shield it how... it's tied into the 120 at the fuse... it's grounded to the Chasis... it makes no hum in my receive. Thats why I added another transformer anyways... when I hooked the fans up to the stock one...it buzzed in my receive. And yes Taz, got the echo board on eBay for $15.00... and I didn't lose any power in this Melaka when I added the echo board. I'm not registered to this forum though... I'll have my friend Sintronic_Cpu try to post the pictures for me. Taz... would you like me to email you directly the detailed pictures of the fans... the transformer... detailed info on how to restore the 10 Meter band while keeping all the export channels intact? I have taken photos of the whole operation... plus I can point out all the places you can mount devices...such as your echo board...roger beep... there are holes on the heat sink for all these items to be mounted! |
Taz
| | Posted on Monday, August 05, 2002 - 7:28 pm: |
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sure d104 please email me! |
Taz
| | Posted on Monday, August 05, 2002 - 7:37 pm: |
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was it the trb-1 echo board? |
Bigbob
| | Posted on Monday, August 05, 2002 - 7:56 pm: |
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A shielded transformer is fully enclosed in sheet metal,no exposed paper or windings.I meant 2 of the same output for twice the amperage e.g. same size.I know about building,took a 4 1/2" square aluminum tube 18" long,installed 5 mj2955pnp to-3 transistors,one muffin fan,one 40 amp transformer,one 317-t regulator,20 4700mfd caps and a speaker grill;voila a 40 amp power supply.Got a one farad cap on output. |
d104 Ohio
| | Posted on Tuesday, August 06, 2002 - 12:00 am: |
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This transformer is fully inclosed... doesn't interfere with anything! Works perfectly! |
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