74196 chip in Frequency counter

[Timescope]

Hi april, What wattage are the soldering irons? I used that method to replace a burnt agp slot on a computer motherboard : I broke off the plastic housing and then un-soldered the metal contacts one by one.
Do you have a "solder sucker", a hand held, spring loaded de-soldering pump ?

Thanks for your offer of help with spares. I have attached a picture of the modification I did to get the tv in question working. Surface mounted components are not available here so I made a small circuit board, mounted a through hole NCP1207 on it and wired it on top of the power supply board.
Please expect to hear from me.
I am using a Latronics 800w sine wave inverter made in Australia and it is solid and reliable.

Timescope

 

[april]

Hi 20 and 30 watts but I also have a 240V 80 watt and one larger at about 120 W
Taking out each pin 1 at a time is a possibility or soldering the new to each pin was what I had in mind. I do have a solder sucker.OK I dont know why those surface mounted parts would not be available. Let me know what you need and I'll check it out here. Perhaps the States does not sell to Sierra Leone. I don't mind posting them on. I am going up to New Guinea in a few months if there is any restriction here there would be none there.

I could not make out much detail on the pic , perhaps a pretty charred area and some heavy solder tracks, maybe some wires from the 8 pin chip

 

[Timescope]

Hi april, that is an ideal range of soldering irons. It would be nice to mount the ic properly. You could practice on an old circuit board. The quickchip flux will help the solder to flow better. I usually apply some fresh solder to a joint before using the sucker.

Our problem is that we do not have a proper spare parts dealer here, only a few Nigerians that bring in cheap goods from China and some of the spare parts for them. Some of the parts are of dubious quality like a 2SC2581 transistor a customer purchased to repair an amplifier that turned out to be a re-marked PNP transistor. Close examination showed that the original number had been wiped off.
You may have heard about the defective electrolytic capacitors that were manufactured about 10 years ago using an incomplete formula that was stolen, costing big name computer manufacturers hundreds of millions of dollars to repair or replace defective power supplies and motherboards. We have them here.

Sorry about the poor quality of the picture taken with my ancient phone. I have attached a closeup and part of the schematic that I had to draw because I could not find it anywhere on the internet.

Timescope.

 

[april]

Oh thats much better , a very complex repair.
I have to order some parts that I need from Vetco.com in the States . Tell me what you need and I will see what I can add on to my order and what it will cost to post to you. I also use Sparkfun and Mouser but the latter has a high post charge US$50 or about 2200 SLL . ( I looked that up ) Vetco and Sparkfun are half that or sometimes free if the order is big enough. I got those new displays from Vetco. about US$25 for 6.
I have not found a supplier for the MSM561RS after quite a bit of looking . They seem to be obsolete. Perhaps I will have to stick a bit of coloured paper with the number 4 on it .

I mess around with Arduino chips and boards including the ATTiny85 and I buy from Radio Control Hobby shops in the States.All of the above are heaps cheaper than buying locally and only a 2 week wait.

I'm fairly adept at soldering and desoldering but I don't use the solder sucker often . You mean use the sucker from the back of the chip on each pin I suppose . I can do that I found my logic probe and confirmed it working by checking my chips again hoping that maybe pin 13 might be going low on each clock cycle but it wasn't.Steady high.

 

[Timescope]

No, it's not complex, just needs some concentration for about 30 minutes. Evidently they are CMOS devices so the usual anti-static precautions will be needed.
Unfortunately US$50 is 220,000 SSL. Our currency nosed-dived in the eighties from $1 =Le0.7 (70cents) to the present rate of $1 = Le4,400. We took an IMF loan to host the OAU conference in 1980 and had to comply with the "devalue your currency" and other conditions. Ten years of war also took it's toll.

The MSM561RS is still available. Here are some of the suppliers I found while searching for the datasheet :

americanmicrosemi.
octopart
**broken link removed**
alibaba

Did you try the logic probe on the ics that are working ? Pin 13 of which ic ?

Wow, you have an Arduino. It should be possible to program a micro controller to perform the functions of the MSM561RS. Please don't ask me how as I have only seen an Arduino in pictures.

I will try to get a list of parts together, thanks.

Timescope

 

[april]

Crikey thats a rapid devaluation. I dont mean to pry but what would the average weekly wage be? and is there much unemployment do you know?
Thanks for the searches , I will check them out. The ATMega328p chips are about US$5 so that would be 22.000SLL wow.
You can make the boards yourself with normal components . I find them very interesting and they are programmed in C or C++ The IDE is free too
https://www.arduino.cc/ and a cheap small board https://www.sparkfun.com/products/9220

No I tried the logic probe on the non working (but I'll have another look at that)and the pin 13 was on the 74LS196 . Thats the pin that taken low clears the display I think . I sort of hoped it might be pulsing low but evidently not. Just fiddling. Checked all the pins , same results as above.

 

[Timescope]

At the bottom end of the scale, $50 -$100 per month , with a degree, a few hundred dollars a month for teachers etc. The sky is the limit for those at the top. Some time ago, BBC reported that our head of anti-corruption earns Le 47 million a month (about $10,000). The majority of the population are in the few dollars a day group that's why I want to find a cheap way to repair damaged LCD screens to bring some joy.

Pin 13 of 74LS196 is tied to +5 and is the master reset pin. See what the logic probe shows on the working chips but take care not to short the pins. If your logic probe has pulse stretching, you should see negative pulses on pin 1 of both ics, 74LS196 and MSM561RS (load and latch respectively)

Thanks for the links. I'll check them out.

Timescope.

Edit: Thanks, I have seen the sites you referred to.

 

[Timescope]

Hi, april,

The Solomon Islands just had an earthquake and small tsunami. Hope all is well.

Timescope