New Member - Long term CR2020 Owner - 'Relay' Board

[brianor]

Folks
New member here - and now need to work on the Capacitor Board and Relay Board on my CR2020
Intend to use the excellent advice from Flakzilla and others on this forum and the excellent repository of information here:

cr2020-relay-board/README.md at main · flakzilla/cr2020-relay-board

Contribute to flakzilla/cr2020-relay-board development by creating an account on GitHub.

github.com

I have owned my CR2020 from new and it is a UK model

My initial question is:
The references in the discussions here is to Yamaha relay circuit board LC-67183-1
But - my circuit board has the reference - LC-67181-1 - on the bottom - see attached image.

In the above discussions the board is also referred to as YEC YE-23V N
On the top of my board is a reference to YEC. YE-27V N - see attached image
Should I be concerned?

Many thanks in advance as I set out on my adventure...

Brian - In Ireland

 

[avionic]

Welcome aboard..

 

[brianor]

Welcome aboard..

Avionic
With your posting record here - I am delighted to be welcomed by you - Thanks
As you have also contributed to many Yamaha CR2020 discussions - who knows - our paths may cross again

Brian

 

[brianor]

Folks
I am at the beginning of my Yamaha CR2020 relay board restoration.
I am using the solution suggested by Flakzilla:

https://github.com/flakzilla/cr2020-relay-board.

I have already had replacement circuit boards made using the info on the above guide - so far so good
I have also studied the BOM list for the components needed to populate the board and have a query.
Am quite new to all this - so please bear with me!
In the list for the transistors is the following information:



Some of the part numbers have a single 'alpha' letter in parenthesis ( )
e.g. - (E) (C) (Y) etc.
Can someone please explain what they mean so I can order the correct parts?

Thanks in advance
Brian

 

[Sparkplug]

Those letters are the hFE (DC current gain) band designators for the transistors. Transistor data sheets usually define them in a small table (normally a single line). Follow what’s given in the Yamaha schematic or Yamaha parts list for your amp. If nothing is specified, then any rating should work but make sure you use the same one for both channels.

If those letters are actually specified by Yamaha, try not to veer off too far or you might end up with current/voltage/noise imbalance in your amplifier line up, between L/R channels, or amp performance in general. The higher rating isn’t always the better choice as it depends on the context of the circuit and what the transistor function is.

hFE bands aren’t universal and different manufacturers use different, but sometimes similar, designators. Always check the data sheet.

 

[brianor]

Sparkplug
Many thanks for the speedy and detailed reply - much appreciated.
In the chart above - the Orig Part, is as you may surmise, is the Yamaha part Number and the Modern Sub is the modern substitute.
I have looked at various examples of the Modern Substitute on Mouser and didn't see an obvious corresponding part. Will look harder and see if I can make any sense of it.
Again - Thanks
Brian

 

[Sparkplug]

Sparkplug
Many thanks for the speedy and detailed reply - much appreciated.
In the chart above - the Orig Part, is as you may surmise, is the Yamaha part Number and the Modern Sub is the modern substitute.
I have looked at various examples of the Modern Substitute on Mouser and didn't see an obvious corresponding part. Will look harder and see if I can make any sense of it.
Again - Thanks
Brian

Check the data sheets for the transistors, not just what Mouser lists, Mouser doesn’t lis different available bands. Attached is an example for 2SA844 E and KSA1015 Y, from your table. They’re not exactly equivalents as far as hFE goes. KSA1015 GR would be a better match if you can find one. In general, If it’s a one off replacement, KSA1015 Y will work but I wouldn’t systematically replace transistors like this.

 

[avionic]

Some of the part numbers have a single 'alpha' letter in parenthesis ( )
e.g. - (E) (C) (Y) etc.

Those letters are the hFE (DC current gain) band designators for the transistors.

trivia : Also color code for the painted transistors..

 

[Sparkplug]

trivia : Also color code for the painted transistors..

You mean the leads? I guess if they’re not in the hFE table, they must be for something …