Icom IC-R5 battery leakage - Page 1
Forum section: electronics / rf-microwave

author: okw
author_rank: Frequent Contributor
timestamp: February 12, 2021, 12:37:04 pm
content: My Icom IC-R5 was left in the drawer with batteries for many years. Sadly the batteries started leaking and corroded a bit on one side of the PCB. The circuit IC3 / R56 / R60 on one the "ears" of the PCB had quite a lot of damage. Otherwise it looks good. The service manual is here:http://www.radiomanual.info/schemi/ICOM_RX/IC-R5_serv.pdfI cleaned with isopropanol and replaced R56 and R60 and it powers up again. However, it does not respond to key press or wheel turn (only maybe 1 of 20 power on/off it might work). Power key works almost every time. If I remove the battery, even just a few seconds, display shows CLEAR. Sound always works. I tried both battery and the power supply.Any suggestion?

author: geggi1
author_rank: Frequent Contributor
timestamp: February 12, 2021, 10:40:29 pm
content: Try to clean off the key buttons and contact points on PCB.Check how the buttons are interfaced in to the cpu.

author: coppercone2
author_rank: Super Contributor
timestamp: February 13, 2021, 03:29:50 pm
content: I can think of way too many things, but usually when I clean I also use some distilled white vinegar and give it a dip in the ultrasonic, then wash with distilled water in a rinse bottle then alcohol but that device looks really miniaturized and difficult to repair in general.Have you considered giving it an application or two of deoxit ? Sometimes that clears up stupid issues with switches. Get one with a high 'cleaning power'.ALso did you inspect under magnification from multiple angles to see if there is any more discoloration ? I would check the area near the immediate damage with a microscope and the other areas further away with a benchtop magnifier.I also recommend taking out all the PCBs and putting everything plastic/structural into vinegar and ultrasonic cleaning it for a longer period of time and also scrubbing it with a brush to really scour the surface and being more gentle with the PCBs.I had a old radioshack multimeter that had damage far away from the battery in a seemingly random area. I did not save it but alot of my time would have been saved if I took all the PCBs out and did full inspection before going for 'obvious damage' because that thing was quite fucked. I would have needed a pace tools setup to fix all that crap with a reasonable amount of effort on such a cheap piece of gear.You could have a leakage path (wrong bias, high z stuff being fucked up, open damaged contacts, intermittent/excessive ringing/bad voltage levels (poor mechanical form of switch caused by poor contact area with microcorrosion or just being clogged with goo leading to long switching times or stupid stuff like not being fulled closed or open (medium impedance))..Now in my opinion ultrasonic and brushing has the potential to eliminate alot of that stuff if deoxit, vinegar, soap, distilled water and alcohol are used appropriately.Be sure to turn up the brightness on the inspection lights, using the maximum brightness based on the reflectivity of the structure you are looking at.

author: coppercone2
author_rank: Super Contributor
timestamp: February 13, 2021, 03:47:32 pm
content: also keep this in mind, when it comes to batteriesthey contain alkali hydroxides, usually potassium hydroxide. Do you know what you get when you mix potassium hydroxide (dry, not fully reacted with air to form potassium carbonate, being in a tightly sealed plastic chassis) with alcohol? You get a super cleaning solution, particularly with ethanol. On one hand its a great cleaner for things like dirty glass, on the other hand it will pretty much devour most things. You want to get rid of this stuff with water andthenclean with alcohol.Not sure if you want to bring a super corrosive cleaner mixed with abrasive smut into switches and stuff lol . Not sure how different chemicals react with KOH, but I know for a fact when mixed with ethanol its a very mean cleaner."PropertiesPotassium hydroxide exists as a white solid powder, but is highly soluble in alcohols like ethanol.Ethanolic potassium hydroxideishighly acidicin nature. It ishighly corrosivewhen handled. It is an effective conductor of heat, and highly flammable. It appears as a colorless liquid."https://sciencing.com/ethanolic-potassium-hydroxide-7483457.htmlThat website even says that the batteries might already have ethanolic potassium hydroxide in them also, so splashing around trying to spot clean with alcohol might not be great either. What I don't get is that I usually use vinegar for leaked batteries, and it does bubble, but the website claims its a acid when reacted with ethanol, so maybe it depends on the battery type. I think they are called alkaline for a reason. Maybe zinc carbon cells are different.Not sure what it does with IPA but I don't think its magically too much better, maybe a little less aggressive (things are usually less soluble in IPA). But for micro contacts, its the last thing you want in there IMO. FLush with water, neutralize if you dare, wash with alcohol then hope deoxit does its magic on your bad contacts.Now the thing that forms when you mix the electrolyte with alcohol might strip the area good and make it look great because it was cleaned with a super acid but you need to ask yourself, is this good for the other good circuit elements to have this weird new chemical stripper splashing around? I would say its too agressive and you should take some time with a bit of sand paper, exacto, chizel, sand paper to clean the area without arbitrarily forming a even more aggressive chemical on the surface which did the damage because the super cleaning action looks great on the first glance.