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#1 Ignition Amplifier

Posted: Sun May 27, 2018 11:52 am
by andrewh
I decided to take apart my SNG Barratt Igntion Amplifier as its definitely on the blink. Now does anyone know whether I can source these part myself and has successful replaced the module and Capacitor(?)
Image

#2 Re: Ignition Amplifier

Posted: Sun May 27, 2018 12:02 pm
by Heuer
Easy to replace although I have never done it. Two screws and four spade connectors. You can buy the generic equivalent here: https://www.ebay.co.uk/itm/Ignition-Mod ... 2235685514

Worth a try for £21!

#3 Re: Ignition Amplifier

Posted: Sun May 27, 2018 2:15 pm
by andrewh
thanks David. There is also the flux capacitor underneath. Now not sure how to check this is ok. Could do with it being ok, as its more complex, a little soldering and correct terminals involved.
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looking on the Googlenet it seems strong advice is to fit the GM module as its the only one unto the job and heat in the V12 engine bay.

umm

#4 Re: Ignition Amplifier

Posted: Sun May 27, 2018 4:50 pm
by Heuer

#5 Re: Ignition Amplifier

Posted: Sun May 27, 2018 8:30 pm
by 42south
Hi Andrew
You are probably one of the first to take the sng apart.
The AC delco chip was the one in the original HEI amp, and has been used in millions of cars in the US
I wonder if the SNG box has an upgrade over the original?

#6 Re: Ignition Amplifier

Posted: Mon May 28, 2018 11:29 am
by andrewh
yes I think the SNG module was an upgrade. The module above is no longer manufactured I have discovered so I will go with an alternative. Thanks David on the suppressor. One thing that was most odd was that under the module when I unscrewed it off the fixing plate was a load of white paint like stuff. All wet! I wonder whether this has come out of the module. Seems like I need to dismantle that to explore! I thought it may have been something SNG used to bond the module to the plate but since it is screwed to that there would be no point. All interesting stuff.

#7 Re: Ignition Amplifier

Posted: Mon May 28, 2018 12:54 pm
by Heuer
That sounds like the capacitor has blown hence the gunk. Dobt there is a big enough cap in the module. Suggest you try just changing the cap first before buying the ignition module.

#8 Re: Ignition Amplifier

Posted: Mon May 28, 2018 2:19 pm
by xroyalnavy
That "white gunk" is probably heat sink compound to get a good thermal contact between the component and the metal casing thus helping keep the component from overheating.
Peter

#9 Re: Ignition Amplifier

Posted: Mon May 28, 2018 2:46 pm
by andrewh
Interesting. It did not come from the Cap as thats below where this was found. It was between the module and the support plate. . If the Cap is designed to stop ignition clicking through the radio it didnt work as it was the worst case of interference I have ever experienced on a car. Still trying to find out which GM module to source. Asked on JagLovers as well.

#10 Re: Ignition Amplifier

Posted: Mon May 28, 2018 2:57 pm
by Heuer
Then Peter is right - the white stuff is heat sink compound.

If you want GM then you need to look for part numbers 1875990 or 830931
Cross-reference-list (any of these should work and I doubt they are different in terms of reliability):

AMC 8131941

BERU
0040401005
ZM005

BOSCH 0227100029

DELCO REMY
1875990
1894322
830931
9348922
D1906

DELPHI DAB125

ECHLIN INTERNATIONAL TP45

FAIRCHILD SH4240 SH4418

FIAT4419628 82369531

GENERAL MOTORS
1875990
830931

HELLA 5DA006623051

IVECO 4419628

LANCIA 4419628 82369531

LUCAS ELECTRICAL DAB125

MAGNETI MARELLI
000094038521
064833010010
64833010
940038521
940038521010
940385521
940385521010
BKL1A

MOTOROLA
AM2
GM1

PEUGEOT 592789

RENAULT 7701021955

VALEO
245515
2595003
CD863

#11 Re: Ignition Amplifier

Posted: Mon May 28, 2018 3:17 pm
by andrewh
this refers to the gloop
Image

#12 Re: Ignition Amplifier

Posted: Mon May 28, 2018 10:12 pm
by Series1 Stu
It's definitely heat sink compound. I've used gallons of the stuff over the years and ruined more shirts and ties than I care to remember in the process.

Handle with care. It's almost impossible to get off your clothing.

Regards

#13 Re: Ignition Amplifier

Posted: Tue May 29, 2018 1:18 am
by xroyalnavy
Haha, that's right, can be a real mess - we used to call it birds%*t when I used to work on that kind of stuff back in my RN days.

#14 Re: Ignition Amplifier

Posted: Tue May 29, 2018 7:20 am
by andrewh
Thanks David. I didn’t spot you post when I last replied I have now ordered one off Amazon ! Gosh the world is changing! Sng do a kit to move the Amp to the front panel but it’s £390 a bit too rich for me though maybe next time !

edit: I bought an Intermotor 15210 which I hope will be ok.

#15 Re: Ignition Amplifier

Posted: Wed May 30, 2018 7:15 pm
by andrewh
just back from a fairly hot test drive and pleased to say the problem seems to have been eradicated. So, I purchased an Intermotor ignition module. It came with the white paste and was a five minute job to remove the old one and replace it. I have to say that whilst I am up and running and its easy, I am seriously tempted to get hold of a second amplifier and make up a spare for the boot. I thought about running extension leads up to the front panel where it is no doubt cooler for the electronics, but on this occasion I went for the easy option. Just cannot say when it may go again. The heat in the engine bay of an XJ12 is enormous. Even less air flow than perhaps a V12 E with its front frames . It would be great to come up with a real alternative. At least the last fail was only when hot and would run again to get you closer to home. Thanks for the help guys.

#16 Re: Ignition Amplifier

Posted: Sun Aug 05, 2018 4:51 pm
by andrewh
Ah, well sadly the problem is back, or more accurately, never went away. I am now wondering whether the coil is the culprit. I see that the coil fitted to my XJ12 is non ballast. Not sure whether this is right or not, as I think I read somewhere that the SNG Ignition kit doesn't need a ballasted coil. Can anyone shed some light on this. Also, I was trying to see what voltage I was getting at the coil when running but my meter was going bonkers . Am I missing something about this ignition system or should it not simply show a 12v or if Ballasted 9 v reading at the coil? Hey ho, its too hot and my brain is not working !

#17 Re: Ignition Amplifier

Posted: Sun Aug 05, 2018 11:20 pm
by 42south
Hi Andrew
Whilst surfing the net I came across the attached diagram. It may be a useful test, perhaps one of our electronics gurus could comment.
The coil supplied with the SNG kit is a Lucas DLB 198, which advertises as a 0.8 ohm resistance and suitable for non ballasted systems. I have read somewhere that the SNG kit even though it still uses the ballast resistor housing for originality, is modified internally and may not have the resistor included.
I do know the Reopus suppliers say that the SNG ballast resistor unit cannot be used with their product otherwise the coil may overheat.

Image

If you Google testing GM HEI module there are many links to info.
Good luck and keep us posted
Cheers
Mark

#18 Re: Ignition Amplifier

Posted: Mon Aug 06, 2018 7:55 am
by 42south
Hi Andrew
I also found the following diagram of the internals of the Ballast resistor, or not. There is no guarantee of its authenticity, but it should be simple enough to test it.

Image

the resistor numbers are A-D 6.8K ohms
B-F 0.3 ohms
Cheers
Mark

#19 Re: Ignition Amplifier

Posted: Thu Aug 09, 2018 6:33 pm
by andrewh
hi Mark, and many thanks for the response and apologies for not replying sooner. I shall take a deep look at this information. I have bought a new coil and amplifier from SNG so hope that this will solve the problem. Fingers crossed . I do appreciate the help . Andrew