Recognize this IC? - Page 1
Forum section: electronics / repair

author: james_s
author_rank: Super Contributor
timestamp: April 01, 2021, 08:18:34 pm
content: I'm trying to fix a marine clock that belonged to my late father. It was badly damaged when a AA alkaline battery was left in it and leaked all over the PCB, he gave it to me years ago to see if I could fix it but due to the extent of the damage I never got around to making much progress until recently. Now after a complete disassembly, lots of scrubbing and patching of rotted traces I have the clock part working but it chimes a random number of times, occasionally it just keeps chiming until I manually advance the time to stop it. I patched up several open traces and confirmed that the signals from the encoder on the hour hand shaft are now getting to the IC and at this point my prime suspect is any of several 1206 ceramic capacitors that got corroded by the leaked electrolyte. Unfortunately I have no idea what value any of them are supposed to be so I'm hoping this is some kind of standard chime IC that might have a datasheet somewhere that might have an example circuit but I have not found much yet. I suspect that 8950 is probably a date code since I recall the clock was purchased around 1990. So far I haven't found anything promising searching for 1152. If I can't find anything I'll reverse engineer the whole circuit and maybe that will provide some clues, although the IC may turn out to be a black box.

author: amyk
author_rank: Super Contributor
timestamp: April 02, 2021, 12:27:27 am
content: Eurosil (now Temic/Telefunken?) 1152A. German company. Unfortunately no other info I could find either.

author: wraper
author_rank: Unknown
timestamp: April 02, 2021, 01:02:40 am
content: Unless you removed those capacitors, likely there is corrosion under them. You will not clean contamination under them by scrubbing. You need to use ultrasonic bath or desolder them. If you want to replace them, desolder and measure capacitance.

author: james_s
author_rank: Super Contributor
timestamp: April 02, 2021, 02:35:02 am
content: Well that's my next step, I was hoping I'd get lucky and identify the IC first but I figured that was probably a longshot. The movement is German so I'm not too surprised to hear that the IC is German. As with most boat things these clocks are very expensive, around $850 and surprisingly it seems replacement quartz movements with a shipstrike chime are not widely available.

author: fzabkar
author_rank: Super Contributor
timestamp: April 02, 2021, 03:00:19 am
content: FWIW, the Eurosil 1115A appears to be equivalent to Intersil's ICM1115A (an 8-pin clock chip which drives a stepper motor).Page 132 of the following document lists several Eurosil TIMEPIECE-WATCH/CLOCK ICs as cross references for Samsung parts:http://bitsavers.informatik.uni-stuttgart.de/components/samsung/1988_Samsung_Semiconductor_Product_Guide.pdfTypical part numbers are e1325B, e1330, e1208, e1444.So I'm guessing we should be looking for e1152A or e1152.

author: james_s
author_rank: Super Contributor
timestamp: April 08, 2021, 06:00:12 am
content: So just to follow up, I ended up reverse engineering most of the circuit and did not really find anything surprising. I also removed each of the capacitors and most of them showed something reasonable although one read only about 6pF. Just for grins I tried a 0.1uF cap I had laying around and that made absolutely no discernible difference so who knows. As it turns out though the electronics were working fine and the problem turned out to be alignment of the gears. There are two parts to controlling the chime. First there is a printed encoder wheel driven by the hour hand shaft, that controls the number of chimes by connecting various combinations of 4 pins to Vcc. Then to trigger the chime exactly at the top and bottom of the hour there is a cam on the minute shaft with a little lever that moves a separate set of contacts, this allows it to trigger the chime at precisely the right moment as the lever drops off the edge of each cam face. What was happening is the encoder was not quite aligned, so sometimes the chime would trigger when it was in a valid position, but other times it would trigger while there was an illegal configuration on the control pins and that would cause weird numbers of chimes. Now I have it working *almost* perfectly, I just need to take it apart again and move it one tooth because every now and then it chimes too many times but it's pretty close.

author: fzabkar
author_rank: Super Contributor
timestamp: April 08, 2021, 11:32:25 pm
content: It would have been an interesting job for Steve Fletcher:https://en.wikipedia.org/wiki/The_Repair_Shop