Radio Reveil - LED clock radio.

[dan.mih]

Hello,

I have found this clock radio made in Romania in 1981. It was an export model for France, Belgium or other French speaking countries. I have managed to repair the display (made by SANYO), one segment was not working. I resoldered all its connections to the motherboard. As I don’t have its instructions, I have a few questions regarding the clock:

1. What type is the clock IC? It is not marked. I could not find anything about the company from Hong Kong (WELKNOWN ELECTRONICS, Model 90996). On the mainboard it has 4 transistors: 2 x A608, D734, C536. The IC gets quite hot during operation. I need to know the pin connections and its datasheet specifications so that I can measure if it gets normal supply voltage.

2. How does the clock get set? Intuitively, with the right knob up, you adjust the Alarm (REVEIL) using the upper knobs (LENT – the numbers change slow, VITE, it’s erased – numbers change fast), and down you set the Clock (HEURE). In the middle (STOP) it should be blocked from any adjustment, but i cand still adjust the time with the knob on STOP.

3. What is the function of the SOMMEIL (SLEEP) button? RAPPEL is SNOOZE and delays the alarm for another 10 minutes. If you want to stop the alarm, on the side of the radio it is a disk AUTO STOP.

4. How come they did not add a back-up battery? At first I thought that in case of power failure, the clock gets stuck on the last hour and minute and restarts from there when the power is back on. But it resets to 7.40 and the display blinks. I consider it is not very practical. Better to wake up 15 minutes later (until they repair the failure) than one or two hours...

[Station X]

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[G6Tanuki]

Is the clock IC a separate chip? How many legs does it have?

[a lot of these sorts of clocks had a 'chip' that was a semiconductor die bonded direct to the PCB at manufacture, then covered with a brown blob of epoxy resin]

if it's a multi-legged chip then it could well be a General Instruments AY-5-1224 or a Mostek MK50253 - these were the go-to chips for quick-and-easy generic designs in the 1970s.

(sidenote - I love the General Instruments calling their chip "1224" to reflect it did 12- and 24-hour timing.. who says sales/marketing geeks don't have a sense of humor?)

[cmjones01]

There was a standard 40-pin chip which did the 'alarm clock' thing, perhaps the GI or Mostek ones that G6Tanuki mentioned. I think even Maplin sold one at some point. It shouldn't be hard to find a few data sheets on line and compare pinouts with what you have. I suspect there are many equivalents.

I had a 'Westclox' alarm clock which used such a chip. The fast/slow setting operations were a pain, and the buttons were those horrible metal bubbles sellotaped to the PCB. The 40-pin chip actually had all its legs bent over the other way and was soldered in to the PCB on its head! The whole clock was, frankly, rubbish.

Chris

[dan.mih]

I am sorry for the delay. It is a 40 pin chip, but not those mentioned, which have 16 pins (AY-5-1224), respectively 28 pins (MK5025).

Yes, the buttons are metal bubbles and make poor contact although they don't look oxidized. I tried to wash them with Isopropyl alcohol, but I could not reach all spots and I did not persist in order not to destroy the tape on top of the bubbles.

[img]************************CdLP2rCH/IMG-20190805-122625.jpg[/img]

Otherwise, I have the clock on for a few weeks. It keeps time OK, although the IC still gets hot during operation. With no datasheet, i assume the power voltage is at the maximum rating or a little above.

I was curious to see if the datasheet mentions an option for back-up battery.

[cmjones01]

There may not be a battery backup facility. These chips tended to use the mains frequency as their timing reference, and certainly the one I looked at had no means of using anything else, so adding a battery backup wasn't easy. It would have been possible to create a 50Hz clock with some external circuitry, but it wasn't built in to the chip.

Chris

[dan.mih]

It is probably a clone of one of the following: LM8361 (Sanyo) or MM5387 (National Semiconductor). Since the display is made by Sanyo, the IC might be inspired from Sanyo, which has maximum VSS=18v. My clock gets 17,2v.

The pins are not the same as Sanyo. The IC's are not interchangeable.

I will leave it as it is and hope it will last