Restore my CR-2020?
- Thread starter joehalo
- Start date
Its how solder joints can "normally" look when the flux isn't properly removed.
4seatPilot
"Broker"
IIRC, Yamaha used the 2SD234 originally. I believe Merrylander recommended the 613 as a replacement, so perhaps someone has been in there and changed the transistors. The current part people usually prefer to use is TIP41c, but I believe the 613 should also be fine.
For certain the resistors have not been changed though. Your resistor choices are fine. I have a mouser project list for the parts if you want it.
mouser parts list link sent by PM....
relay is out of stock, alternative is the MY-02-DC12, but Mouser doesn't seem to have it.
If the backside of the cap board is badly burnt, you may have trouble with mounting those resistors. If you look, you'll see that they are in series, so an alternative would be to remote mount a single 56ohm resistor. This one should do the trick:
40F56RE
For certain the resistors have not been changed though. Your resistor choices are fine. I have a mouser project list for the parts if you want it.
mouser parts list link sent by PM....
relay is out of stock, alternative is the MY-02-DC12, but Mouser doesn't seem to have it.
If the backside of the cap board is badly burnt, you may have trouble with mounting those resistors. If you look, you'll see that they are in series, so an alternative would be to remote mount a single 56ohm resistor. This one should do the trick:
40F56RE
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bktheking
Gitter Done!
Yes, typically these are the traces that do get damaged. The issue is two fold- air flow and heat sink size on the to220's. There is a post on Ak in the yamaha section where someone moved the transistors to a different location and used wires and a connector to connect up to them.
Honestly, most of the work is done getting to the back's of the boards- you've done that. Go with Steve's list, order the parts- pay close attention when recapping that board with the main caps- there's a strange + - marking for one of the caps- easy to put it in backward. Take lots of pics prior to redoing whatever you plan on redoing.
Honestly, most of the work is done getting to the back's of the boards- you've done that. Go with Steve's list, order the parts- pay close attention when recapping that board with the main caps- there's a strange + - marking for one of the caps- easy to put it in backward. Take lots of pics prior to redoing whatever you plan on redoing.
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bktheking
Gitter Done!
Before you get into it- make sure you can set bias and check the DC offset at the speaker terminals- there is no provision to balance DC- it's done by closely matching the differential pair. If it's 10mv or lower this is acceptable. If not the diff pair should be replaced. With a good matched pair installed it should be as close to zero as the circuit allows.
4seatPilot
"Broker"
I've done that a couple times. I think I posted on it... works great, but has to be done right. Or else... KAPOW!
4seatPilot
"Broker"
Sounds like the voice of experience... watch those 458s! :tongue:
No, they've been replaced.
4seatPilot
"Broker"
Mount the new ones well off the board for cooling... Kink the leads so that they are supported by the kink on the component side of the PCB and not just the solder on the solder side.
How are your traces? The better the condition, the fewer hours it's been used.
Sent from my Nexus 4 using Tapatalk
How are your traces? The better the condition, the fewer hours it's been used.
Sent from my Nexus 4 using Tapatalk
