Stalker XX/President Madison PC411AD Repair

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Mars 2-4-7
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Stalker XX/President Madison PC411AD Repair

Post by Mars 2-4-7 » 26 Nov 2017, 14:21

Hi,
I wonder if anyone can assist me in finding some information about a Stalker XX which I hope to have restored & aligned. I have ordered a new capacitor kit & some Schottky diodes, but before I start I have noticed a badly burned resistor (R169). I have searched the net & so far haven't been able to find what the correct value is.
Also I have heard the Schottky diodes may, or may not, require a 2SC2999 transistor. Any ideas or information would be most gratefully appreciated!
Cheers!

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Re: Stalker XX/President Madison PC411AD Repair

Post by Techquest » 26 Nov 2017, 20:36

R169 22ohm .5watt don't bother with the 2SC2999 the original transistor has better gain.
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sonoma
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Re: Stalker XX/President Madison PC411AD Repair

Post by sonoma » 26 Nov 2017, 23:14

there is some info in the secret cb books on cbtricks.

http://www.cbtricks.com/pub/secret_cb/index.htm

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Re: Stalker XX/President Madison PC411AD Repair

Post by sonoma » 26 Nov 2017, 23:17

defpoms site has the full tune up section on his site

http://www.radiomods.co.nz/

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cb4ever104
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Re: Stalker XX/President Madison PC411AD Repair

Post by cb4ever104 » 27 Nov 2017, 19:09

Mars 2-4-7 wrote:
26 Nov 2017, 14:21
require a 2SC2999 transistor. Any ideas or information would be most gratefully appreciated!
Cheers!
I did this 2SC2999 mod a couple of times . It worked ok in a couple of radios , and not so good in others . As Techquest says , the original transistor works well enough , and to be honest I would leave it as is . I remember my ol' m8 on here RD250 gave us all some technical info on his findings . To be honest there's tonnes of stuff on the Internet and this forum about it .

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Re: Stalker XX/President Madison PC411AD Repair

Post by Mars 2-4-7 » 28 Nov 2017, 22:09

Thanks for all your reply's so far, & I apologise for the time it has taken me to respond. Somehow it had all got trapped in the spam folder! Anyway, your response was most appreciated. The radio is going to have a new set of cap's fitted supplied courtesy by a very helpful guy in Canada- I'd really like to give him a mention by name but being new on here, I'm unsure of the rules. He's been very helpful going to be my first point call to supply such parts now. Then it will go away for a full service & alignment. I've been wanting a nice Stalker XX since I was about 12years old, & now 37 years later (you can do the math(s)), I've finally got a clean example & just want it sorted out inside to release it's best potential. I really want to learn all can about the PC-411AD board, so any tip's, advice or any info at all will be most appreciated.
Whilst I'm on here, I have some NOS single & dual active filters from the same period. Being active, they aren't supposed to lose any sensitivity, but are there any downsides? Has anyone tried these, or has any experience with them, good or bad? Thanks again everyone, I appreciate your time.. Cheers!

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Re: Stalker XX/President Madison PC411AD Repair

Post by cb4ever104 » 30 Nov 2017, 13:35

I have 2 PC-411 Madisons . The analogue clock President variant , and the Uniden badged digital clock version . Doing a recap is always a good idea on 25+ year old radios . The only other modification I did on my 2 was to add an 80 channel pic with +10khz option . I removed the HI BAND crystal filter board . I'm not sure if the XX has this expansion board fitted or not ? Anyway . Mine got removed and a pic installed , as they're more reliable . I reused one of the front panel switches for the +10khz . My clarifier had also been "unlocked" , which is something I dislike . So I put it back to the way it was . Oh , and I also fitted a 220V mains transformer to my Uniden one , and jumpered the digital clock IC so that it would run on 50hz and not 60 .

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Re: Stalker XX/President Madison PC411AD Repair

Post by KlondikeMike » 30 Nov 2017, 16:23

Mars 2-4-7 wrote:
28 Nov 2017, 22:09
... The radio is going to have a new set of cap's fitted supplied courtesy by a very helpful guy in Canada- I'd really like to give him a mention by name but being new on here, I'm unsure of the rules. He's been very helpful going to be my first point call to supply such parts now.
I admit. It was I that helped Jonathan out. I provided a capacitor kit that will get that radio back in service for the next 30 years. He should be receiving it this week. A radio worthy of the attention. Good luck with the restoration.

https://www.ebay.ca/itm/142009612889

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Mars 2-4-7
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Re: Stalker XX/President Madison PC411AD Repair

Post by Mars 2-4-7 » 01 Dec 2017, 18:31

Thanks again, Klondike Mike! Your a star! And this weekend I'll get a list together for the other PSU Cap's we spoke of.. I'll drop you a line soon.. Cheers!

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Re: Stalker XX/President Madison PC411AD Repair

Post by Mars 2-4-7 » 01 Dec 2017, 20:46

Thanks Sammy for the info on your Madison's.. This is all interesting stuff indeed! I have just ordered an original 'Circuit Trace w. Photofact' workshop maunual dated 1980 from the US. Between this & the link Sonoma kindly supplied I intend to read & re-read as much as I can until I know this radio inside out. I had originally intended to fit a UK40 board & the filter I previously mentioned, but on balance I think it maybe more in keeping just to have a really good service, align & recap job to keep her as original as possible. It would have been nice to keep the original cap's in a way, but they must be past their best by now, & if they leak it could potentially damage the PCB which is why I ordered the one's off Klondike Mike. I'm glad I did as he has provided me with some excellent information & support beyond what I could have expected for the (very reasonable) price of a capacitor kit. He's also very honest, which is another reason why from now he's going to be my first stop for such components in any of my gear. I'm still rather curious as to whether these active crystal filter boards are a good thing, or if there's any negative side effects in performance. The included transistor on the board is supposed to restore gain, but like most things, there's often a trade off, & I don't want to ruin a well designed circuit. And it's not as if there's the sort of radio traffic like we had back in the day where we were tripping over each other's adjacent channels.. Anyway, thanks again folks!

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Re: Stalker XX/President Madison PC411AD Repair

Post by cb4ever104 » 03 Dec 2017, 21:47

There's also a mod to remove the annoying thud when changing channels .

viewtopic.php?f=53&t=50983&p=454772
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Ex GM0 , now EA5 .
Handle "Fortune Hunter" back in "the day"
Radios ....? Anything that says "TAIWAN R.O.C" on the back.

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Re: Stalker XX/President Madison PC411AD Repair

Post by Mars 2-4-7 » 04 Dec 2017, 11:38

Thanks, I'll check that out also..
It seems my Stalker illness is getting worse- just purchased another, even cleaner, XX which came with a similar, but AM only, Stalker XII! So looks like I'll need another couple of capacitor kits soon! I've also got original period workshop manuals coming for both now. That should keep me occupied over X-Mas..

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Re: Stalker XX/President Madison PC411AD Repair

Post by cb4ever104 » 04 Dec 2017, 11:55

Mars 2-4-7 wrote:
04 Dec 2017, 11:38
I'll need another couple of capacitor kits soon!
Panasonic gold capacitors seem to be the peoples choice . To be honest I just use normal ones . I'm doing my silver Grant at the moment . Think the complete set cost me about €7/8 .

Sammy
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Paul aka "Sammy". (108) PY60 Old Paisley DX Group (RIP Rab Markie)
Ex GM0 , now EA5 .
Handle "Fortune Hunter" back in "the day"
Radios ....? Anything that says "TAIWAN R.O.C" on the back.

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Re: Stalker XX/President Madison PC411AD Repair

Post by Mars 2-4-7 » 04 Dec 2017, 19:13

I see! There must be all sorts of good & bad cap's out there, & for what it costs in time as much as money, we may as well fit decent ones. The cap's that Klondike Mike is supplying are of reportedly good quality & he's been very helpful, so that's reassuring. And does anyone know where I could get a spare clock LED display? Two of the three radio's clocks are fine, but the third radio has a segment missing. It appears the display is of one complete block, rather than a set of however many 7 segments. I wonder if they are the same pin outs/dimensions as a regular alarm clock/clock radio.. I do have a frequency counter that would fit, but just wouldn't look original..Cheers!

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Re: Stalker XX/President Madison PC411AD Repair

Post by cb4ever104 » 04 Dec 2017, 19:48

Mars 2-4-7 wrote:
04 Dec 2017, 19:13
And does anyone know where I could get a spare clock LED display?
Good question . And to be honest . No . But you can buy almost anything these days from China . The display is listed in the schematic as an "SL-1494-11T" display .
Capture_0012.jpg
A Google search on that doesn't bring up anything . Also , it could possibly be an issue with clock IC (LM8361D) . I don't have my radio handy , so I can't help much with that . You should be able to get each segment to illuminate without removing it . If the segment lights then it could be a bad solder joint , or the IC . If it doesn't then you'll need to remove it and try and track one down . Also , you might be able to switch it with another led depending on which segment it is .

Sammy
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30TM060
Paul aka "Sammy". (108) PY60 Old Paisley DX Group (RIP Rab Markie)
Ex GM0 , now EA5 .
Handle "Fortune Hunter" back in "the day"
Radios ....? Anything that says "TAIWAN R.O.C" on the back.

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