Got my hands on it now.:Biggrin2: Some progress, the VDR is s/c, measures 7 ohms (off pcb).
It has X1429 671S (S could be a 5) etched on it in tiny letters......Anyone identify?
Printed over that is what looks like 7491 (larger and upside down). Not certain about the 91 (charred)..... I can't identify it......Anyone else?
The supply is 12v (confirmed by dazling) via the "frazzler", which does have a band on one end, now o/c. (diode?)
The one above the "frazzler" was detached from the pcb at one end (see pics from dazling) . Removed from pcb for easier access to
repair the tracks. That one also has a band, and tests like a diode (think it's marked 6G 7A, can't identify that either).
Not too bothered about that one, can reconnect.
The "frazzler" feeds two LM 2931AT-5 voltage regs (5V o/p) the first one direct, and the second via the detached diode above.
I'll post a diagram of cct area (if needed) when I get time to draw one.
If I bypass the "frazzler" with 12v (VDR off pcb) I get a 5V o/p from each, as expected.
A guess for the VDR (about 2cm diameter), if it can't be identified, and assuming 14-15v from an alternator.
Caps across VDR and regs are 35v. Reg i/p is 40v max continuous, 60v transient.
Reg spec here.
View attachment 80031
So, guess about 20v.....Make sense? Also thinking 1N4148 for "frazzler"? (smd pads are shot anyway).