Sir bushtech . . . . . .
If this complete system / unit is SOLELY
using 2 D cells (ANSWER ?)and with their combined 3VDC output, I am suspecting that the JD16-L IC is being a one of a kind custom design unit and just stuffed with Zetex transistors, as that is their all defining forté, in their making of effficient, low voltage use transistors.
The electromagnet seems OK. Do they fail?
Considering the equipment and the conservative power involved . . . vewy-vewy wawely . . ..
Could it be a rotary encoder???
Why ? what is there in that whole system that you perceive as being rotary in nature . . . . . and forbid . . . . that needs to be decoded ?
I don't know ALL
of the JD16-L potentially possible internal functions, but I highly suspicion the need of the driving of that black ? Transformer ? beside it to create upwards of 200 'ish volts of output, that is then to fed across board to then be rectified by the blue cased HV diode, that is located beside the LARGE reddish brown poly cap.
That cap will be charged up and its charge cycles will then be repetetively dumped into the primary winding of the ferrite rod cored ignition transformer.
. . . .with a sparking at the secondary windings ends at electrodes at the burmer assembly . . . . the incoming gas is lit. The third wire sensing electrode detects flame presence, to shut down the gas valve in case of no flame developed initially or having a later flameout..
To the right of that cap is the Hi Voltage ignition coil, being all hermetically encased in STYRENE and has its high voltage secondary, being wound as six series aiding separate windings. Its 5K' ish . . .upwards ? . . . . outputted secondary voltage goes into the two imbedded black wires . . . likely being silicone, as they are going to the hot burner area.
(On that same topic, you have two braided WHITE wires in the units wiring bundle , does that pair also route to a thermally HOT area, as that might be braided fiberglass . . . . . . .since the 1930-1960's adhesive clumped asbestos wiring . . . .icht bin verboten !.Ja !
NOW BE MY EYES AND TELL ME :
Do you confirm that is being a quite small, black E-I cored transformer,that is located just to the side of that JD16-L IC ?
Then, on the other side of that t-former , can you also make out the cap value and voltage rating of the green poly cap ?
Also the numbering of the nearby TO-92 cased transistor, BUT don't break it, bending to see, as its being heavily encapsulated overall and at its wire lead base.
: A brite lite, used with a SHINY silver mylar foil strip (snack food mylar bag sourced) makes a GRE E E E EA A A A A T
. . . . .a la Tony the Tiger . . . mini, CLOSE quarters inspection mirror.)
( It makes the normal, mini inspection or dental mirrors look like large CYCLOPS
While you are on your roll, additionally check the marking on the only other seen, top side mounted TO-92 transistor, over near the earlier mentioned BIG poly cap and blue diodes area.
Busy tracing. Red line leads to ? common ? of S8550 transistor.
[Mod edit: changed NPN to PNP]
Here are your given PNP Y2 (S8550) surface mount) and NPN S8550 items specs.
. . . . . . I can see the non use of a continually running pilot light as on a pipe line natural gas, never ending feed.
Now with your . . . . maybe a decade . . . use of this unit ? does this unit have a low battery alarm, or do you have to treat it like a smoke alarm with annual replacements . . .(if not sooner).
Talk to me . . . . .
73's de Edd.....
Why is "abbreviation" being such a long word, in consideration of its definition ?