Simpson 260 Series 3/4 meter repair - can't find replacement resistors - Page 1
Forum section: electronics / repair

author: hydrogen maser
author_rank: Regular Contributor
timestamp: July 27, 2016, 05:09:25 pm
content: I am repairing a Simpson 260 Series 3/4 - it is a Frankenstein of a series 4 meter movement and face with a series 3 board that has been modified with a series 4 200k pot across the meter. Don't even know what to call this beast. Anyway, repair is going well except for one thing - Some of the resistors are out of tolerance (all 1%) and I can't find replacements for them. There were a total of 6 resistors out of tolerance and I was able to replace 3 of them with modern resistors by putting new resistors in series or parallel to get the right values. There are 3 resistors that I just can't find anywhere - 15M 1W 1%, 80M 2W 1%, and 20.2M 2W 1%. That last one I could just use a 20M (if I had one) in series with 200K. I looked on ebay, Amazon, Digikey, etc and nobody seems to have anything like these values or anything close to them in those wattages. Any ideas where to look for these?

author: hydrogen maser
author_rank: Regular Contributor
timestamp: July 27, 2016, 09:16:25 pm
content: Found a 5 pack of 10M 1/2W 1% for a few bucks so I can use those to build a series+parallel 15M 1W, but still can't find the high wattage, high value 20.2M and 80M ones. Tempted to contact MikesRadioRepair on youtube because he seems to have these kinds of resistors and might know where I can get some.

author: singapol
author_rank: Frequent Contributor
timestamp: July 28, 2016, 05:45:04 am
content: Try Element14,https://www.element14.com/or it's subsidary Newark,www.newark.com/They have some branded TE CONNECTIVITY / CGS and Ohmite. Saw a 15M 1W listing but at 5%. The rest you need series or parallel? Also bigger wattage available at 1% but pricey.

author: hydrogen maser
author_rank: Regular Contributor
timestamp: July 28, 2016, 10:52:22 am
content: Thanks for the suggestion of element14 singapol, I had heard of them in the past but forgotten about them, bookmarked for future use. Looks like the Simpson is going into the pile of "fix it later if I can find the obscure parts for a reasonable price". Element14 lists the parts that I could make work, but it does not make economic sense to buy the resistors new to fix it. Perhaps I will find a box of high value/wattage resistors at a hamfest that will fit the bill. I really like the design of this meter - it just switches in various resistor paths for the ranges to measure dc and additionally a couple of diodes to measure ac, pretty neat and it was fun to work on.

author: mzacharias
author_rank: Frequent Contributor
timestamp: July 28, 2016, 11:51:09 am
content: Must be for the 5000 volt range - you really need to measure that?

author: hydrogen maser
author_rank: Regular Contributor
timestamp: July 28, 2016, 12:05:23 pm
content: Actually the high voltage 1000/5000 range was what I wanted to use it for. My other meters top out at 600v and I wanted to use the Simpson for measuring 500v to 2000v dc low current supplies (in the single digit ma current). All the other ranges of the Simpson are covered by my DMM's.