The Defpom Forum, for RadioMods, S&M Software and Music by The Defpom

Warf135

Yea, I reckon 32 bands ought to be just about enough Dave!

Although some how i dont think the Jumbo can handle that many

Warf135

Hi Dave, No i do not have an eprom programmer... however i do have a home made eprom reader which i use to find passwords on locked out laptops, maybe i could use that to read this eprom (if I knew which pins were SDA and SCL). The eprom itself seems to do the UK offset in this mod. its got a UK81/F...

Warf135

Hi Sue, thanks for the interesting reply. I have just tested for swing on my known good President Lincoln and that is showing no swing either, so it would appear that you are correct in that the Jumbo is probably working ok and that neither of my SWR/Power meters are upto the job... :doh: Any sugges...

Warf135

Cool Scott, I just didn't wanna clog up the forum with big files, but with your ok, here are the files:

: K40 Mic Schematic; k40sch.gif (78.84 KiB) Viewed 5455 times

k40_man.pdf: K40 User Manual; (2.26 MiB) Downloaded 933 times

Warf135

Here is couple of pics from original K40 user manual which may help some people to visualise the mod: k40mod.JPG K40rigmod.GIF A common fault on this microphone is bad solders on the main capacitor which can give same symtoms as a radio that has not had the mod done to it. EDIT: user manual and Sche...

Warf135

Hi Guys, I am trying to find info on the eprom conversion thats in my MK1 Ham Jumbo. The only identifier I can find on the eprom board is the number 88081 (or it could be 88031), Anyone Know anything about this eprom board? My radio has this eprom to give UK 40, but then it seems to have a seperate ...

Warf135

Hi Scott, Thanks once again for your prompt reply. I will probably never use AM - I just wanted to make sure that the radio was right whist I had it on the bench. I'm sure my old lafayette 1200 would do 5 watt carrier and swing to about 10 watts (that too was cybernet if i remember right, but probab...

Warf135

Radio Make = Ham International Radio Model = Jumbo Mk1 PCB number = PTBM059COX - Main board PTOS006AOX - VCO\Crystal board PTPW007COX - Power Supply board PLL number = PLL02A Test gear available: TRIO FC 756 frequency counter, basic scope, swr/power meters, dummyloads Thanks to Dave and Scott in my ...

Warf135

Hi Scott, Thats a good plan, removing all the mods and putting the radio back to standard i may end up doing that eventually if i cant work around the mods and get the radio working properly. I've already had to re-wire the beep switch because it was wired wrong and had just cut the audio, so the de...

Warf135

Hi Dave, thanks for your quick reply. Yes the radio still has the 2 large wirewound pots on the underside near the power supply board... they are both set at maximum at the moment... i had been wondering what they are for, so thanks for that info. It has me puzzled also, why with an eprom the guy wo...

Warf135

Radio Make = Ham International Radio Model = Jumbo Mk1 PCB number = PTBM059COX - Main board PTOS006AOX - VCO\Crystal board PTPW007COX - Power Supply board PLL number = PLL02A Test gear available: TRIO FC 756 frequency counter (yes I finally upgraded from the zetagi c57! lol), basic scope, swr/power ...

Warf135

As long as the power supply lead for the radio is putting out around 13.5vDC you should not have any problems putting a new radio in... If I remember right, trucks run on 24v and you need a convertor to reduce it to 13.5v If this convertor has gone bad it could have been the cause of the amp chip bl...

Warf135

Hey Kruser, thanks for that info.. I have since seen these radio's going for about $30 brand new, so in that case your probably right, its uneconomic to repair. However, if it turned out to be a simple fix that the person could repair themselfs, then it could possibly be worth doing... Interesting t...

Warf135

Ok, this is a cool, but pointless mod I've done to an old maycom em-27... I've made it remote controlled! I can now turn it on and off and go up and down the channels without even touching the radio 8-) The mod was done using parts from an old portable TV. Check it out on youtube: http://www.youtube...

Warf135

Unfortunately, I have been unable to locate a schematic for this radio, so I can not help...

If anyone has the schematic for this radio, please post it on here

Warf135

So there is no audio going out or coming in...ok, let me try to find a schematic for this radio and I'll look into it for you.

Warf135

Were you using an extention speaker on the radios? A faulty extention speaker could blow the audio chip in the radio. if it was a faulty antenna or coax I would have expected the RF power output transistor to blow and not the audio chip. Let me confirm: The radio is working fine, TX power is OK, RX ...

Warf135

Are you positive that the radio IS on frequency correctly on all bands and all modes? If the frequency counter is reading correctly on all other bands, and on LSB on the "bad band" is also reading correctly, then it would appear that the frequency counter is working correctly. If possible ...

Warf135

are you sure there's not a fault with your patch lead or your power meter? normally if there is a fault with the radio it will not show any swing on the internal meter either

Warf135

Have you tried another microphone on the radio?

Warf135

Job Done! :dance: Now the Lincoln looks blue when in receive: lincRX.jpg And red when in TX: lincTX.jpg The colours are a lot deeper than shows in these pics and it looks very nice :lol: In the end I used a subminature relay, switched by the TX line of the mic. The relay switches a Bi-Colour LED, po...

Warf135

Thanks Dave and Scott, Hadn't thought about making a circuit to come direct off the TX line of the mic, that would be easier in some ways and certainly safer in respect of not pulling any other parts of the radio out of allignment. I'll have to have a play around I think and see what happens... usua...

Warf135

Hi, I'm planning a mod to a Lincoln, where the display changes colour when you TX. I have it basically figured out, but need to know where to "safely" connect the TX and RX LED's. I can easily find a couple of points with my test meter and schematic, but dont want to just tap off from anyw...

Warf135

Update: I've now tested all components in the echo chain and have come to the conclusion that the MN3008 chip is kaput. Since a new chip is about £15-20 and I would hardly ever use echo anyway, I have decided not to bother and have grounded the echo fader to kill echo altogether. Beep has now also b...

Warf135

Thanks for great info. I have replaced LM324 as a spare was to hand, but no change. My scope isn't working at the moment, but I checked pins 2 and 4 of MN3101 with high impedance frequency counter and read approx 9khz from each pin to gnd, so assume that that chip is ok. So far all resistors and cap...

Warf135

Hi Scott, Thanks for reply. The TX led remains lit at all times, and the audio works fine, but just looses echo. The voltages: pins 1+3 MN3101 = 8.00v that stays when echo gone pin 3 + GND LM324 = 4.20v that stays when echo gone pins 1+5 MN3008 = 8.60v that stays when echo gone this has got me puzzl...

Warf135

ok, I've now changed all electrolytic caps as a matter of course. This has had no effect on either the echo or the beep problems. both sliders and the 50kpot for repeat speed test fine on the meter. am i right in thinking that the MN3008 and MN 3101 chips are to do with echo? and the LM324N is pream...

Warf135

Here is Echomaster plus schematic - courtesy of Rick Jackson -euro radio co.

Warf135

Hi Scott,

Pleased to say the new forum search is working perfectly.

Thanks.

Warf135

Mic Make and Model: Sadelta echomaster plus PCB Number: EMP-2 Symptoms: Microphone will echo for 3-5 seconds then echo will fade out. audio remains perfect, just with no echo. If mic is left for a while it will again echo for 3-5 secs. What is working: Microphone is working properly other than this ...

Warf135

Thanks warhorse!

UPDATE 12-05-2009: I rebuilt my speech processor and now it's working fine again. I found out that ALL of the 8 pin DIL chips are very cheap TL061CP low power J-FET input op-amps.

Warf135

still looking for schematic, part layout, user manual.

Warf135

Thanks for your reply Warhorse, you describe it to a tee. The guy I got it off said it could be powered by batteries or the power supply. Didn't take too long to figure that it needed both forms of power for it to work. :roll: since my last post I was getting reports of a pretty bad buzzing coming t...

Warf135

Hi Scott, Thanks for the quick reply, but i'm sorry to say that the search is still not working right. It now searches as it should... but fails to find anything at all :roll:. I've tested it with things I know are in the forum, like lincoln and maycom and nothing is found. Strange! :?: :?: Norm (ak...

Warf135

Hi All, What I have here is a Zenith P-202 Speech Processor , circa 1982, made by Zenith Electronics here in the UK. I have managed to figure out and re-wire the in and out's to suit my Lincoln (with the addition of a relay to stop the Lincoln's display going weird when it's plugged in) and it's sou...

Warf135

Hi Scott, I'm having problems with the search feature in the forum, here is the error message: General Error Could not delete old search id sessions DEBUG MODE SQL Error : 2006 MySQL server has gone away DELETE FROM phpbb_search_results WHERE session_id NOT IN ('0000b272f14e85f8283f5d42a690541e', '0...

Warf135

Hi, Shorting the mic socket on the 104 midland should not have damaged anything. Pins 2 and 4 on the mic socket must be shorted for you to get any recieve audio (then disconnected under tx), maybe your mike isn't wired quite right. I'm not sure about the other midland but would suspect similar. Norm.

Warf135

Hi, Open up the radio, and you may see the colour of the wires going to the socket. Or you can find the pins you need easily with a continuity tester: 1, turn power switch of radio on 2, connect one test lead to switch contact 3, probe the pins on the power socket with the other test lead 4, when yo...

Warf135

Radio Make and Model: 1995 Radioshack trc1014 handset (aka maycom/cherokee AH27) PCB Number: 27RFCR-B and 34010008 PLL Number: unknown Test gear available: trio FC756 frequency counter, Motorola S-1355A swr/power meter, dummyload, standard multimeter (and Farnell DTS 12 'scope when I get round to fi...

Warf135

Link option 5 on the solder-links to enable 5kc shift. To use, hold M1 and press M6. In 200, 400 or 600ch mode the radio will display the change, however, in 80ch mode the display does not change but the frequency does. The .25 uk offset is not applyed in 400 ch mode, however it is still displayed o...

Warf135

Hi James, Rick has a couple of switches, but I didn't want to take his last supplys. I have seen them on an american site when I was looking for an extention speaker flylead for this radio, at that time I didn't know I needed them, and now can't find the stie again. Will post here when I find them.....

Warf135

Hi Rick,

you can reach me on this e-mail address: normsweb AT clara.co.uk

Thanks,

Norm.

Warf135

Help! Cannot access PM. when I click on the "you have one new message" link i keep getting this message:

Sorry, but you cannot initiate private messages, users with special ranking can message you, and you can reply to them, you just cannot start a new message thread.

Warf135

Hi Rick,

Thanks for your prompt response. how much are the switches?

I was planning to replace all 7 at once (mic gain, beep, dim, loc/dx, F.lock, PA and NB), but if they are way expensive, then I'll have to just replace the two that are actually broke at the moment.

Norm.

Warf135

This is a 1989 lincoln. Hi folks, After many years of use the Mic Gain and Beep switches in my radio are worn out and not working correctly. I have stripped them down, cleaned them and re-fitted them, without much success. (I think the springs are kaput) Do any of you know where I may get some new s...

Warf135

:D :D :D YAY! Sorted! :D :D :D Turned out to be a surface mount ceramic cappy on the underside of the processor board... I can't tell you which one, because i couldn't work out the component locations in relation to the schematic... visual inspection with a magnifying glass and bright light confirme...

Warf135

now changed most of the cappy's on the board with no success

any other ideas?

Warf135

just changed all elect. caps around IC306. the radio is now only 257khz out. here are the new testpoint readings:

TP304: 36.400/36.500 drifting
TP305: 16.441
TP302: 10.240
TP306: 6.20

These readings are more like it, but still not quite right...

should i change all the other caps on this board?

Warf135

Hi Scott, Thanks for the info, I have just checked all the testpoints you mentioned with dubious results: TP304: unstable, jumping between 15-18 mhz and when doublechecked jumping between 12-16mhz TP305: 16.432mhz TP302: 10.230mhz TP301: unstable around 12mhz (maybe out of range on my counter) TP306...

Warf135

This is a 1989 President Lincoln. Proc.board is: Uniden PB121AD. has been opened wideband(26-30) by jumping L312 to the 10k resistor next to RR301. Bought this radio secondhand and found it has this fault: :x the radio works perfectly from 26.0000 to 27.9999mhz but, from 28.0000 to 29.9999mhz is 280...

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