PK-232 battery question.

Discussion in 'Working Different Modes' started by K1APJ, Dec 30, 2019.

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  1. K1APJ

    K1APJ XML Subscriber QRZ Page

    I've lost track of the exact sequence of events, but at various points in time the backup battery in the PK-232 was both a leaded coin cell and a holder for three AA cells. I think the original PK-232 had no battery at all, but I am not certain.

    Obviously the three AA cells give you a nominal 4.5V, but I don't think I have ever seen a coin cell above 3 volts. I am currently restoring a PK-232 that has the coin cell installed, but it is dead. It is wired through a diode into the 5 volt rail used to power the non-volatile memory.

    Was there a special coin cell for this purpose, or did they get away with using a standard 3V unit?
     
  2. KB0MNM

    KB0MNM Ham Member QRZ Page

    They used a coin cell rated at something like 3.6V, and the part number was of the CR-2032 or CR-2036 series. The same cell was used in other AEA TNCs. More information would be best found through the www.timewave.com website*. Randy purchased all of the TNC business from AEA, leaving some of the RF components ( like antennas and RF analyzers ) to a different company which also has the abbreviation AEA. That is to say, one of two companies named AEA is still in business- yet if you are looking to service / upgrade their TNCs- Timewave is where to go. When/if you replace that cell: 1. Polarity is important. The holder can be 'counter-intuitive' that way. Note that the terminals of the new battery can usually best be identified by a + symbol, which is generally on the largest ( cup ) shaped area. 2. Metal tools can short the battery during installation. Some folks use 'plasti-goop' or other tool handle insulation on the tips of a small needle-nose plier for this type of work. Others just take care about the boundaries or use blue painting tape. 3. There is a pretty good amount of tension ( intentional ) on that coin cell holder. Secure all of those screws in a bottle and find a low countertop for the work. 4. Old battery acid is probably present, and may be nearly invisible. Rubber gloves ( maybe what the XYLS used to use for dish-washing ), safety glasses or goggles, extra-clean water ( or eyewash station ), and baking soda ( to neutralize ) would all be advised. An old toothbrush and gravity can come in handy for gobs of white acid. Compressed air / canned air / even blowing through a straw can just spread it to worse locations. So you might say that I have been-there-and-unfortunately-done-that. B.T.W.- There is a Facebook group now for the PK-232 and similar. If you are looking for the newest software / updates- and do not want to get the info from Timewave- that may be of interest. As far as I have seen, they do not discuss local packet ( digipeater/APRS ) use by geography very often. *Some coin cells went into holders, and therefore had no soldering required for the leads. Be aware that a corroded battery can cause dangerous fumes with soldering heat, as cadmium is not good to breathe.
     
    Last edited: Dec 30, 2019
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  3. K1APJ

    K1APJ XML Subscriber QRZ Page

    Thank you for your response. Yes, I have been through the Timewave site, there are a couple references to a lithium battery but no part numbers. I think my original unit came with the AA cells but purchase of the MBX option later on provided a lithium cell. The unit I have now (not my original unit) has the coin cell soldered in, there is no holder.

    My PK232 will not get enough use to justify any major expenditures or upgrades, but I was curious about the battery. Actually, my main interest at this point is probably the AMTOR capability, would be interesting to contact a few die-hards to see if we can get an AMTOR ARQ qso established. I found a copy of PC-Pakratt and a computer to run it so I am close to being ready. There are a few soundcard apps that will do AMTOR FEC but not ARQ.

    Anyway, thank you for your insightful comments.
     
  4. KB0MNM

    KB0MNM Ham Member QRZ Page

    You are most welcome. If you do solder, consider that new 80 watt iron rather than an older 20-25 watt model. Larger tips can make the job pretty easy- too small equals too slow. Liquid flux and braid can get the last bit up faster, so you do not need an assistant to pry things loose. The new iron has an added benefit- it may get hot enough for the new R0HS solder compounds. There is a solder compound called 'Chip-quik' or similar that also allows the solder to stay molten longer- it can be a real plus in removals. It is expensive, and has a special flux which is necessary. MCM was recently sold to one of the larger firms- Allied or Newark- they should have it.
     
  5. KD5RKO

    KD5RKO Ham Member QRZ Page

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  6. W9GB

    W9GB Ham Member QRZ Page

  7. KB0MNM

    KB0MNM Ham Member QRZ Page

    From what I have seen on the Digi-Key website, you can get CR-2032 batteries from different vendors- one claims theirs has a higher current capacity. Do consider that the cell can be put in a holder, but that going to a larger one ( say from 20mm to 24mm ) might make the assembly too large to fit inside the area. The metal cover strictly defines the amount of vertical space if you need to 'tilt' the holder. Other than the battery- few folks have reported any serious problems with the PK-232. Most involve not having built a real RS-232 cable ( all hadnshaking signals from de-9 to DB-25 ) or setting the level to match their radio. One op did have a bad 7406 and a few transistors dead in the PTT circuit. Last comment- callsign is required for transmit.
     
  8. K1APJ

    K1APJ XML Subscriber QRZ Page

    Very good. Well, I went completely through my "new" PK232, it had severe mechanical damage to the case, the THRESHOLD pot was broken, but no real damage to the electronics. I removed the coin cell and it is indeed a CR-2032 with welded-on leads. I am going to revert to the 3-AA cells, I have a holder for them and it will be a bit less fuss. I did make up proper cables and have no problems with connectivity, either to a true RS-232 port or through a USB converter.

    Anyway, I did the alignment (which was wildly off) and the unit does work. The sensitivity of the MARK and SPACE demodulators is not identical, so I will need to look at that; it takes 10 mV for a full-scale MARK but 40 mV for a full-scale SPACE. I don't think that is a real problem but I would be curious to understand it. Decodes no problem, I have not put it on the air yet but I am sure it will work. I did let it sit on 14.105 all day looking for packet activity, saw an active station in Colorado and one in Texas but that is about all I saw from my Connecticut QTH.

    I have one computer left that will run DOS so I am playing with PC-Pakratt II. When I get a little more comfortable with the software I will see if I can strike up an AMTOR sked, just for giggles.


    Thanks again.
     

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