The spreadsheet gives the original SCR as 2N2329 400V 1.6A 0.2mA gate current. There is a 2N2329A only 20uA gate current but not needed here. It's possible to use Spice sims if the circuit really needed changes, but I would plop in one of the SCR's I mentioned earlier.
That schematic has different parts - 6k8's on the switch ladder, MOV, 3.3MEG, 220k, BY133 etc. so might be some mistakes or a different rev.

 

Thank you everyone for the posts. I was able to fix my Elna foot pedal because of the info here.
My machine started running as soon as it was plugged in. Replacing the capacitor C2 (16V, 22uf) fixed it. See attached pictures.

 

My almost 50 yeras old ELNA TSP sewing machine began some time ago to stop working now and then and recently it did nearly never worked.

At the end of my problem searching I found that my problem was bad solderings on the circuit bord in the foot pedal (Type 447300-1). A couple of solderings looked completely broken and several looked more or less suspicious in a 8x magnifying loupe.

After resoldering of all connections my foot pedal now works again.

 

Thank you everyone for the posts. I was able to fix my Elna foot pedal because of the info here.
My machine started running as soon as it was plugged in. Replacing the capacitor C2 (16V, 22uf) fixed it. See attached pictures.

 

Great info on this post. My Elna stopped working been awhile troubleshooting electronics at the component level, couldn't find anything wrong on the board but having a look a the schematic it made me check the hi/lo switch which ended up being the culprit. Managed to get it working with some manipulation but if it fails again I will bypass it into hi or fast mode. Thanks.

 

Great info on this post. My Elna stopped working been awhile troubleshooting electronics at the component level, couldn't find anything wrong on the board but having a look a the schematic it made me check the hi/lo switch which ended up being the culprit. Managed to get it working with some manipulation but if it fails again I will bypass it into hi or fast mode. Thanks.

Isn't it interesting that so many times when the trouble is thought to be in the complex electronics, that it is actually in some simple mechanical part of the system.

 

Thanks to Anthony's post on 6/2/2020, I was able to repair the foot pedal for my daughter's Elna Super. The spreadsheet included in Anthony's post provided the identity of the semiconductor enclosed by the wrap-around heat sink on my daughter's foot control circuit board - marked TA 230. The semiconductor was identified as an SCR, model number 2N2329. I found this exact SCR at Mouser Electronics (mail order USA). The SCR is manufactured by Central Semiconductor. The SCR fits perfectly into the wrap-around heat sink.

Prior to the repair, the SCR would heat up after a few minutes of use, and then the machine would increase speed to full and remain at full speed until power was disconnected, making the machine unusable.

After checking all of the on-board capacitors and resistors, I replaced the original SCR with the new one, and the foot pedal now works perfectly. This thread on All Circuits was the most helpful in diagnosing the problem, and identifying the SCR.

Thanks to all the contributors to this thread.