• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Yamaha CR-820 - guidance and possible help needed

Hi!
Yes, I'm trying to get this unit up and running. Still a long way to go. Need to get the amp section running first. Need to order all the parts and get them replaced. Seems that some are out of stock. I have not tested the lamps yet as the unit is in protective mode. I think I will go with original lams at this point.

There seems to be some noice coming from the realy, but it is hard to tell at the moment. I might replace it all together. Nice unit you have there. Hope to get to that point too. But I have also the aother pcb's to recap, so it will take a while until i get there. But, please cheer me on :) I need that! Studied electronics in high school and worked as a technician some years after graduation at the Swedish rail road (radio communication and fiber optics mainly), but have not done much work like this in a long time. But it is fun and exciting to see if I can get it working. This is an amazing forum with some really helpful people, that also has a load of knowledge that comes very handy when you are a bit rusty like me. Thank you for posting!
 
Hi!

TR707 ksc1815 seems difficult to find, out of stock both at Mouser and Digi-Key. Also checked on Newark as suggested. They no longer keep that transistor in stock. But 2SC1815 seems available. Can it be swapped with that instead? See link below. I also understand that that pair should be tested for hfe balance. Is 50 pcs enough?
https://www.mouser.se/ProductDetail/Central-Semiconductor/2SC1815-PBFREE?qs=u16ybLDytRZLUNBf8BQ9Lw==

I also have a question regarding the TR707,8 that is bent toward the heatsink. Can they be cooled in any other way, but using their own heat sink? I know that there are heat sinks avalable for cooling transistors. Or is it best practice to leave as is?

Since the avalability of the different transistors seems a bit sparse. Is it advisable to look if any other transistor can be ordered that would be good to have at hand? The once that need hfe balance or any any other that out of experince often fail? Just want to make sure I get most of what I need in this first order. I do understand that I might need to do a second, but it also speeds up things having more at hand. I also have a free shipment as things are now. What about incandecent lamps?

I will aslo check that the relay is marked with 12v before I order a new and place the order, as suggeted by Avionic.

Again, thank you!
 
You could use the KSC1845 but those are out as well . it has a higher voltage its basically the difference.

But the 2SC1815 is the original designation. Only thing I noticed from mouser is they don't say what the gain ranking is .

Might order a bunch more than you need and measure to find the rank you need if they are mixed up gains.

Nashou
 
Hi!
Well, I did order a chunk of 2SC1815, but have also the others, but on backorder. Once they arrive I can swap. I guess I can at least use these as a mock up in order to get the unit up'n running.

What matched gain is prefered on the transistors?
 
Hi!
Thought so, but always good to ask. So the 2240 in the bdent.com link will work as subs for TR707,8 transistors, or the mouser link?
 
JorgenSWE said:
Hi!
Thought so, but always good to ask. So the 2240 in the bdent.com link will work as subs for TR707,8 transistors, or the mouser link?
Click to expand...
Yes.. But there to expensive.. You might need up to 15-20 pieces to get a matched pair.
 
Ok, I will search online closer to "home" to see if I can find this transistor. If you find any place that holds it to fair price, let me know. Tnx!
 
Hi!
Managed to actually find the transistor 2sc2240 at a national vendor. A bit on the expensive side, but on the other hand, I didn't have to pay for international shipping.

Now it's just a waiting game for the orders to arrive. And then to get to work.
 
Last edited:
Hi!

Finally the Mouser order arrived today. It took a crazy route through Europe befor finally arriving today. Somehow the relay was missing from the order. Must have slipped when ordering, so it was not added tonthe order. Anyways, I will now start replacing the damaged components. Hopefully we will breath some life into this unit.

I will be out of the country on a business trip during one week mid May, I hope to have made some progress before I leave. I will report back as soon as some progress has been made. Wish me good luck!!
 
JCC transistor 01.jpg Like so many of us, I also seek these KSC1815. I did find someone on ebay that is selling them at a fair price, so I ordered ten of them. They arrived in the mail today, come to find out what he sent me is JCC1 815Y N42. I neglected to read the small print on his ad. The small print does say this part number, so I am unfortunately the loser. Not looking at his small print, he advertises KSC1815. I suppose I am now stuck with these. The guy says this is the new part number that Onsemi is now using in place of their KSC numbering system. I did a search of these JCC transistors, and find nothing about them!! Have any of you encountered these JCC transistors? Are they really reliable replacements for the KSC1815? Or are they yet another example is a Chinese counterfeit?
 
Last edited:
Jorgen, Thanks for your thoughts. I did the same Google, and found that French web site. That site is the only one I can find that mentions these JCC transistors, and claim they are made by Motorola. If that really was the case, wouldn't google come up with more information on these? I remain skeptical, and would feel more comfortable with an Onsemi product.
 
I came across a source at Amazon for the KSC1815. Problem is, I would have to buy 2000 of them for $185. That works out to 9c each, so the price is right. I could take a gamble and buy them, keep 100 or so for myself, and sell the rest at a small profit in hopes to recover my investment. It's a popular transistor, so perhaps this is a good idea????? I could sell on Ebay in lots of 100 for, say, $15 each lot? You all here on AK may have them at cost, of course.
 
You must log in or register to reply here.
Back
Top Bottom