Modified Ham International Jumbo

[George EI7KO]

Whst do you think of this? Done it last year. Has a Superstar 3900 board in it now. Frequency readout, UK fm module and a few other bits and pieces. Took a while to do but it was worth it and the best part is that it does not drift all over the place like a stock jumbo. Have it hooked to an RM station 550 base amp and an Antron at 45 feet. Works great.

http://www.youtube.com/watch?v=eLIIG-od9RA

PS how do you attach Pics on this forum?

[PoisoN]

I have one with a Dirland SS3900F board in it with frequency read out also. RM KL203 linear amp built in. Coverage 24.785-29.595mhz

Much more usable and better sounding than any jumbo board but jumbos are good looking

[cb4ever104]

PS how do you attach Pics on this forum?

I think you need 10 or more posts .

Sammy

PS I don't have a Jumbo

[George EI7KO]

Yeah that looks good mate. I have a few of them here (another of which is not working and easier to convert than to fix). I love the look of them. They were never a great rig in standard trim. Big bloody box with not a lot inside them. The superstar 3900 lends itself quite well to the conversion as the frequency counter fits in quite nice and it is a very accurate one as well. The conversion itself was handy enough to do and was mainly soldering and extending wires to the front control switches and pots. The most difficult part was seperating the two boards for the channel readout where it is directly soldered to the board on top of the channel selector, the two boards are soldered together at 90 degrees to one another. But as I wanted both the channel and frequency read out to line up on the same level I had to seperate them and I used an old hard drive cable to make the connections. Also I had to do away with any of the dual pot controls for the Coarse/Fine and the RF/Mic gain and convert them to single pots. Not hard but a pain in the bum trying to get the right value pots as they are an odd one used for the Coarse tune. Its a 20k pot on the 3900 and I could not find one anywhere and ended up using a 22k pot which left it more stable and easier to zero on frequency. I have tested it here on my test equipment and she's spot on frequency. I have two mikes for it an Opek handheld powermike and a Sadelta Bravo plus. Other equipment here is a Ranger 2950f and a Yaesu FT920. I'll have to clock up some posts to get some pictures up then of the Jumbo.

[cb4ever104]

Can you still "call it" a Jumbo if you change the main board ?

[PoisoN]

Are your meters still accurate though? Ive found mine to be out by a few S-points even with the Vr's turned up full. My Rf gain is very aggressive though with the slighted little turn i can gain locals to 0 on the meter, I dont know what value of variable resistor pot has been used though perhaps If i change is value it might let more RF though to the meter? I didnt build this one i bought it already modded.

Are your meters accurate?

[bigpimp347]

i'm all for jumbo mods, but my only argument is this..
why a 3900 ???
surely just buying a galaxy saturn would be easier ?? i bought mine for £80
buy a jumbo and a 3900F and then do the work makes it costly..

i think most of the common or good boards have been tried in a jumbo,
3900, ranger, superstar 2000 multimode 2, concorde 2 and the 3 of any..

what board would be a contender for a jumbo ??

saying that i have a jackson here and a marko mk3 chassis, both just waiting to be mated

[zephyr]

The Jumbo above needs a green LED to mach the counter, as it is it looks odd.

Putting a Uniden boarded radio into a Jumbo has to be a labour of love, as they say but it's worth every hour spent on it when completed.
I've fitted a MK1 and MK2 148's also a Jackson and a 3900, and I have two more lined up to be fitted with MK2 148's that'll be zero switching like I did with the 3900.

It's not quicker to fit a different radio in than it is to repair the original one, not if it's done right.
Most of the wires have to be extended with the original colours of the donor radio, otherwise it looks a mess and all the wires on the switches and controls of the Jumbo are fitted through the holes and bent over, making it a pig to get then off without melting the switches.
That alone can take hours, then there's all the brackets you need to make it fit and cutting the chassis, that's something you have to be very careful to get right the first time, there's no second chances. The frequency counter fitting is another one you have to get right the first time, the thin plate it fits to is very delicate and bends easy.
The list goes on and on and on. At the end of it all there's the satisfaction that you've got the radio you've always wanted with looks and good performance.

The only problem is keeping hold of it, cause sooner or later someone will see it and make you an offer you can't refuse.

[PoisoN]

The Jumbo above needs a green LED to mach the counter, as it is it looks odd.

I know mate i thought the same apparently he had a green display to fit but he mate some how damaged it, so he had to fit the uniden display but it has the origional channel change he said that was a pretty hard job. See i bought mine like this i didnt do the modifications.

And i wouldnt know where to start to change the display myself wouldnt even know where to purchase one.

[bigpimp347]

And i wouldnt know where to start to change the display myself wouldnt even know where to purchase one.

biggest bloody hint

http://www.lc-led.com/Catalog/departmen ... gory/50/10

[koberk]

Any pix of the inside of the 'Jumbo' Conversion.
I've got a very tatty-looking Concorde 3, and the PCB is looking for a new home...

[zephyr]

This is the 3900 I did this year and it has a green LED. The fan comes on in FM mode only.

[George EI7KO]

Are your meters still accurate though? Ive found mine to be out by a few S-points even with the Vr's turned up full. My Rf gain is very aggressive though with the slighted little turn i can gain locals to 0 on the meter, I dont know what value of variable resistor pot has been used though perhaps If i change is value it might let more RF though to the meter? I didnt build this one i bought it already modded.

Are your meters accurate?

Well I set them up with an RF Gen and used all the corect pots and trimmers. So yes to answer your question mate. You'll find whoever did it prob used the original Jumbo Pots which will work but will make the functions very agressive all right. I changed all the pots out for brand new ones with all the correct values. The RF and Mike gain pot values on the 3900 are 1k linear pots. They are both perfect and progressive the way they should be. Also I ditched the internal supply and went with an external one. I've a 50A Mass supply here to run everything here. It could just be a case of the meter in yours being tired.

[George EI7KO]

Can you still "call it" a Jumbo if you change the main board ?

I call it the "Super Jumbo Mk1" LOL

[George EI7KO]

This is the 3900 I did this year and it has a green LED. The fan comes on in FM mode only.

Thats a lot tider inside than mine let me tell ya. I just cut a hole in the back panel to let the rear panel of the 3900 to protrude out. Mine is a constant work in progress and i'm always messing with it so there are wires every where inside it. But i always preferred function rather than form...lol. Whats the big capacitor for beside the supply board?