montgomery ward 719a conversion help

[mastercare]

Hi bit of a long shot, but thought the cb forum could help, i have a montgomery ward 719a cb which i want to convert up to 10 metre band, i understand its very simerla to the cobra 146gtl but i have the conversion for that , but i need the schmatic of the above rig cos coils caps etc all seem to be laid out different, can any one help with this rig perhaps circuit or component layout..i know its very old. but worth a shot..
many thanks
paul

[lbcomms]

At the very least you'll have to make up an extra crystal oscillator for it, but performance will be lacking in some areas (clarifier range and thermal stability) if you take the simple way out.

Changing the PLL can give you 2MHz to 3 MHz continuous coverage in 5KHz steps, but it's a fairly involved conversion. Did one about a year back:

viewtopic.php?f=53&t=49419

That's for the Australian version called a "Hornet II SSB". It's identical to the Montgomery Ward 719A apart from the brand logo on the front panel...

[dt307]

I also did one and took the easy easy way out
Just swap out the pll 5kc step and clarifier will work normal and retune the rx and tx and it will be great with no rx loss issues if it's just a strait 11m to 10m conversion
BUT as Sue as said she has done one and she is 100 percent correct if you are thinking of 10m and 11m coverage well that's a different ball game

I could get about 1meg of coverage before rx started dropping out. The idea of switching in varctors is a great idea but only 10m was needed so I left it as is

[mastercare]

Hi guys
thanks for the super quick reply, no i don't want it on both bands, just 10 metres. now the crunch Ive never converted a CB before and if you guys can sort me out with the what to do steps i would be very grateful, as of yet i have no circuit of the rig or schematics.
any help or copies of how to conversions you have done would be great...
by the way my late dad bought the rig in the early eighty's from the states and its just siting here doing nothing.
thanks
paul

[dt307]

Did I write up a wile ago for not the same but a close model
viewtopic.php?f=53&t=51088

Will fill in the blanks later ad in work atm

Not sure if Sue does a board?

[lbcomms]

Hi guys
Ive never converted a CB before and if you guys can sort me out with the what to do steps i would be very grateful

It's an early "non expandable" (as in can't be expanded by cutting traces and rewiring) radio, and might be a little ambitious for a for a first conversion project. It will involve at least the purchase or construction of additional circuit boards to fit to it.

You'd be better off with an MC145xxx, PLL02A, or MB8719 based radio - change one crystal to get you roughly in the 10m area of interest, then cut a trace or two and rewire to get exactly where you want to be.

i have no circuit of the rig or schematics

Look for a service manual and schematic for a Realistic TRC-451, easily found online.
Apart from the dimmer on the realistic the insides of the TRC-451 radio are identical.

[mastercare]

ok all thanks alot for all your inputs , it gets worse though today i clicked on the wrong link on a eBay sale, im now the proud or will be soon owner of
a Intek Tornado 34s Ssb Cb Radio?
not sure if i can do anything with one these?
once agn thanks guys for all your help...
paul p/s happy xmas everyone

[dt307]

Yes it's a 3900 I think ept3600???
so 10m ain't a problem

[lbcomms]

a Intek Tornado 34s Ssb Cb Radio? not sure if i can do anything with one these?

Much easier radio to convert, by either / both PLL programming or swapping crystals.

A common variant uses a 14.46 MHz crystal and a 16 MHz VCO. Changing the crystal to 16 MHz will give you 28.505 to 28.945 MHz.

Yours may be different, post come basic information on it such as PLL type, crystals fitted to it, and does it have a 16MHz or 37MHz VCO frequency?

Once you've given that, I'll be able to explain in more detail. Also, what test equipment (frequency counter, power meter, multimeter, dummy load, and oscilloscope) do you have and know how to use?

[mastercare]

Hi Guys
well there may be light at the end of the tunnel yet...ok when it arrives ill strip it down and see what crystals pll etc is fitted regards equip i have DVM oscilloscope 100mhz just bought a freq counter yep dummy load, the scope i may need some practice on that lol, guess if conversion goes ok it will req realignment rec tx etc...ok thanks agn for all your help guys.....

[dt307]

hold the thoughts give nick blackspirit a pm he has a nice little board that will convert that to 10m a treat

[163TM847]

.

[Admiral]

Seems a lot of faffing about to me when you can get a half decent second user entry level 0-30 set for around £150. But hey, break a leg if you want to have some construction fun.

[lbcomms]

when it arrives ill strip it down and see what crystals pll etc is fitted

Looks like you'll have two ways to go then, the second radio you have will be the easiest to convert though (no extra circuit board needed). If you want to do is as an interesting project or for sentimental reasons, you could always do both of them

Let us know here what PLL chip and crystals are fitted to the second radio and I'll give you the finer details on converting it. Also, what part / how much of the 10m band do you want to cover?

[mastercare]

lHi admiral
yes you could call it faffing around, but when i bought a icom290d a few months ago which had no audio for alot less than £50 my mates said the same thing..but i stripped it down and after a few nights fault finding found a leaky cap in the squelch circuit ,,now i have a fully working old but good 2 metre multimode.. Hi lbcomms regards freq it would be nice to go as high as the 10 metre repeaters fm< when band is open> and really usb on the lower freqs i guess but beggars cant be choosers- so that would be 29.200-29.300 usb and fm repeaters 29.550-29.700 but thats in an ideal world, lets get on 10 metre first i guess, also black spirit that board looks good is that for the rig im buying or the montgomery ward?
cheers agn
paul