project part alternatives

Thread Starter

mdidomenico

Joined Mar 3, 2019
18
i'm attempting to rebuild a project from 90's, but i'm not sure on substituting parts.

the project calls for an LM837. it looks like TI still makes these, but only in SOIC form. Ideally i'd like a DIP form (breadboarding) and (4) single chips vs (1) quad chip. i can't seem to find anything that matches the specs at digikey of the LM837 in DIP. can anyone recommend something

it also requires a 78L03 voltage regulator, but those are also not available in through-hole. would an LP2951CN-3.3G also fit?

the final part i can't match up is a transformer. the device is a primary/secondary winding, but the only markings near it are "5mh" and "n=40"
i can infer from the device that the primary is driven from an IRFZ34 mosfet and it should be running at 200Khz frequency, but that's it. is that enough to be able to match such a part to digikey or tell me how to wind my own? i have a collection of torroid cores and magnet wire
 

dl324

Joined Mar 30, 2015
12,439
understood on the SOIC adapter, i have a few here, but they're damn hard to solder.
Are you using solder paste? I solder SC-89 with paste and an iron with a conical tip. My problems are caused by not using enough paste.

Removing without a hot air tool is a pain.
 

Thread Starter

mdidomenico

Joined Mar 3, 2019
18
Are you using solder paste? I solder SC-89 with paste and an iron with a conical tip. My problems are caused by not using enough paste.
Removing without a hot air tool is a pain.
no the last time i tried i used a fine point needle and solder wire from a spool. i managed it, but i ended up getting a whisker or two across the leads. which was a pain to see yet alone remove.

i'll have to hunt around some more and see if i can find some old stock in DIP somewhere, if i can't find an alternative. i don't do enough soldering to warrant picking up a more expensive station and a microscope
 

dl324

Joined Mar 30, 2015
12,439
no the last time i tried i used a fine point needle and solder wire from a spool. i managed it, but i ended up getting a whisker or two across the leads. which was a pain to see yet alone remove.
Reflowing the solder should clean up solder whiskers.

i don't do enough soldering to warrant picking up a more expensive station and a microscope
You can buy used on eBay. I bought a couple backups for my Weller W-TCP for around $30 each. I had to replace the heating element and was unable to solder for a couple weeks while I troubleshot the problem and ordered the part. I have an iron on my hot air station, but I don't like it.

I received one of these as a gift. I should have bought one decades ago.
2196756.jpg
I use it when I drill PCBs. It magnifies, illuminates, and protects my eyes from dust.
 
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