2830/lincoln no bargraph

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warhorse
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2830/lincoln no bargraph

Postby warhorse » Tuesday 1st Aug 2006, 15:07

HI . pres Lincoln the newer type board I found the transmit power was turned up all the way this has caused the bar graph not to work' ( or I could be barking up the wrong tree) i.e. respond, the Lincoln isn?t deaf and quite the opposite on all modes I have started off looking at the receive strip from the Ariel skt transistor diodes caps as of yet no joy any ideas anyone'' using a second TX signal i.e. am/fm does produce a signal on the meter but at VERY close range about a foot components checked as far-c113,q119,d101,102,d126,d127,q101,all ok ongoing. The fmboard-and cpu board are ok interchanged to prove otherwise In tx the bar graph is ok.

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Rick
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Re: 2830/lincoln no bargraph

Postby Rick » Friday 4th Aug 2006, 22:19

Check Q108 Emitter 0.00v Collector 0.00v Base 0.70v in all modes bot in ssb the Collector 0.50v Emitter and Base at 0.00v, also check D111, D112, D117, D118 and IC101 Pins 1,2,3,5,6,7,8,11,12,13,14 should be at 0.00v Pins 8,10 6.80v full squelch pin 4 8.00v pins 9 1nd 10 1.70v no squelch. Hope this helps. Lets us know how you get on.

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warhorse
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2830/lincoln no bargraph

Postby warhorse » Saturday 5th Aug 2006, 14:53

Hi Mr Rick, just noticed the reply, cheers n beers for the quick responce will have a crack at the ole linc at the weekend as i have 1lincoln and a( 2830 with the graph fault. and using the cpu board from the 2830 to try kill 2 birds with 1 stone as they say.

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Postby warhorse » Thursday 10th Aug 2006, 16:38

HI, Rick took your good advice in the end replaced the ic101 with a skt took a working IC 2902n from a working ss360 still no joy, checked all diodes, did notice by lifting d101 that signals became more intense-by injecting a carrier to the Lincoln and not having to take the ariel-dummyload out to rx a lo rx signal I also noticed a continuity short to the bios, board stages? by bushing the dimmer in this stopped the short(seamed like a short??), found the lead from light bulb was terminated to the on off control re earthed to the mode switch ok now no short-still no bargraph changed all the diodes around the 1st front end having had leaky diodes in the past and no analogue way of checking them at the moment I replaced all, the headache continues thinking of changing all caps in the final stages all in Pico pondering on the thought??any ideas r welcome.

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Rick
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Re: Re: 2830/lincoln no bargraph

Postby Rick » Friday 11th Aug 2006, 6:42

It not a good idea to just change components, it?s best to find the fault first, you needs to do some voltage checks I gave you a voltage of a transistor and IC to check? As for IC101 in 35 years of repairing radios I have only replaced this quad op-amp 6 times in any radio. It?s probably a good idea to check some voltages at transistors and let me know what you find or you could send the radio to me and I will repair it for you.

Rick (Euro Radio Co).

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Postby The Defpom » Friday 11th Aug 2006, 16:41

I have seen the IC fail once in a 2510, but it gave the opposite fault, showing all bars on the meter all of the time.

The meter is actually fed via the CPU PCB, as the CPU switches between inputs using some surface mount transistor switches, so a fault is possible at that point (all the inputs go to the CPU PCB, the TX power, RX signal, Mod and SWR, and are then selected by the CPU and fed to the meter circuit).

I once also had a similar fault, and I found the cause was a burnt out track on the rear of the RIT PCB, which I think was caused by the CPU PCB chassis touching joints on the main PCB as it was hinged upwards, so it may pay to have a glance at the PCB and see if the track is burnt.

warhorse
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2830

Postby warhorse » Sunday 13th Aug 2006, 16:23

Hi all TA for the feedback''any way checked all the caps 1 was a very low value so changed it. Checked the m-6 switching transistors you mentioned, traced it back through the circuit via the loom a brown wire to the freq readout board pin 21 etc, checked all wires for breaks r ok, checked the burnt track info from rit -TA Scott for da info. No joy, all ok. Back tracked the information again that Rick asked me to check for the third time' guess what no joy-all voltages r ok well within my test conditions by using a second 2510 to trouble shoot from, is very handy. TA for the offer to repair the radio Rick but joking apart id never live it down ''teehe'' so you know the answer to the question but cheers anyway.

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Re: Re: Re: 2830/lincoln no bargraph

Postby Rick » Sunday 13th Aug 2006, 22:47

If you lift the collector of Q311 (on CPU board) and inject 5mV you should see the bargraph go to about S5, also what is the voltage under strong signal at pin 1 of the CPU connector J276.

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cpu board

Postby warhorse » Tuesday 15th Aug 2006, 15:35

HI Mr. Rick Ta for more feed back actually I found the pin on the CPU of j276 was around 0.64 of a volt, and on the air( ssb ) all over the shop. so to cut a long and uninteresting story short I have used the 2830' CPU in a mk1 Lincoln and the bargraph in that radio works fine very well on 28mhz dx so the problem remains on the board. Going by the diagram most of the avenues r tested from jp34 using a generated sig jp34 is the most active point and the bargraph'.
chris-warhorse.

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Re: Re: Re: Re: 2830/lincoln no bargraph

Postby Rick » Wednesday 16th Aug 2006, 4:45

I do not know where JP34 is connected to and from? If the fault is on the Main PCB it is really easy to fix, you will find the bad component with RF signal generator and Scope. As you have told me all the voltages are a ok, the fault must be a stage which as gone low gain, so the only real way to find to find the fault (with the replace it and hope method) is to inject signal and scope the output of each stage it that simply.

Rick.

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Re: cpu board

Postby Rick » Wednesday 16th Aug 2006, 4:47

warhorse wrote:HI Mr. Rick Ta for more feed back actually I found the pin on the CPU of j276 was around 0.64 of a volt, and on the air( ssb ) all over the shop. so to cut a long and uninteresting story short I have used the 2830' CPU in a mk1 Lincoln and the bargraph in that radio works fine very well on 28mhz dx

so the problem remains on the board.

Which board?

Going by the diagram most of the avenues r tested from jp34 using a generated sig jp34 is the most active point and the bargraph'.
chris-warhorse.

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lincoln(which board)

Postby warhorse » Wednesday 16th Aug 2006, 17:34

Hi, all these replies spoiling me you r'' J34 is on the main president lincoln board its a wire link that supports the rx circuit to the 1st mixer i.e. q101. like u say using a sig gen and a scope for component checking should find the fault as of yet i have not located this annoying fault with this process.

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Rick
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Re: Re: Re: Re: Re: 2830/lincoln no bargraph

Postby Rick » Thursday 17th Aug 2006, 3:19

With two radios you should be able to find the fault in a very short time by checking signal levels between one radio and the other. Q101 is not the mixer it is the RF Amp or front end the mixer is Q102 which is an N-Channel FET if you have had this transistor out you have probably zap it as they do not like static. One think I would like to know is the bar graph working on any mode AM, FM or CW? If not try injecting 0.5mV at pin 3 of IC101 this should give you about S3 to 9 depending on how VR101 is set, if by doing the above test and the result is good, check Q108 may be short check diodes D111, 112, 117 and 118 they may show good on a DVM Diode test but bad in circuit, it is good idea to check how much current the RX strip is drawing. One cap worth looking at is cap C40 I once had one go low capacities.

One think you probbley know is to keep the signal generator low about 0.6uv or the AGC will clamp, you could disable the AGC of course.

Rick.

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Postby hamguy2 » Thursday 23rd Oct 2008, 13:16

hey rick, the fellow from the trucksite has asked me to ask you is there anymore parts involved with the 200gtl clarifier or is it just that certain crystal or xtal 2 you said any resistors or caps or is it just the xtal, thanks david nsw australia

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Rick
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Postby Rick » Friday 24th Oct 2008, 0:22

hamguy2 wrote:hey rick, the fellow from the trucksite has asked me to ask you is there anymore parts involved with the 200gtl clarifier or is it just that certain crystal or xtal 2 you said any resistors or caps or is it just the xtal, thanks david nsw australia


Cross posting just gets you ignored.
Keep in the post you started with.
Rick.

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Re: lincoln(which board)

Postby KC7NOA » Tuesday 15th Nov 2011, 18:31

warhorse wrote:Hi, all these replies spoiling me you r'' J34 is on the main president lincoln board its a wire link that supports the rx circuit to the 1st mixer i.e. q101. like u say using a sig gen and a scope for component checking should find the fault as of yet i have not located this annoying fault with this process.


Did this ever get resolved?


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