Yamaha5000
Never settle for 2nd best
Thank you and I agree with you 100%
OK scouring the thread one more time I see this as the TO-220 dual rectifier "updates"? Yes?
Yes, that is correct.
Hi @jayfree , I've built one of these using your awesome PCB (thanks!)...have checked what the voltages are that you get from the Left and Right pins on the terminal strip (NB+ and NB- on the schematics)? These should be about -40v and +40v (according to schemos....depending on PCB version), but I'm getting -60v and +60v (same as B+ and B- values)....I've double checked polarities and desoldered and tested all components. The only diff is for the diode arrays, I used SDURF3040CT/SDURF3040CTR. Going into troubleshooting mode, but any input would appreciated. thx!
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Thanks. i kept all the orig resistors except for one since they were w/in 1% tolerance...that blew me away. But, to be sure, i'll swap new ones in for all of them. Thanks for confirming the values you got on J3. If the resistor values doesn't change the values, it's likely that the target values of +/-40v on +/-NB are taken under load with the full circuit active.
Swapped in new 22ohm/33ohm 3 watt resistors and for whatever reason, the issue with two of them overheating stopped. I'm not totally sure why that would make a diff, but will take the win. The thermal imager shows a strong hotspot on one of the little resistors on the relay board. I'm going to check the voltage and current on that resistor and compare voltage with the schematics... Anyone have any idea what current levels one should see on the relay board? Those little resistors are a quarter watt I'm assuming, so I can probably back the max amperage out with a little math.
The 1.8k next to TR717 and either the 1k or 10k next to TR708. Another issue that's likely related is there's no -25v output at the post (the +25v is fine), so today am going to trace from the -NB input to find where it's dropping out. Part of the issue is the pcb is pretty brittle under TR715 and I've had to do some 'surgery' to recreate the broken traces in a few spots...all of this is a bit of a fools errand since the new relay pcb of your design will be here in a day or two from JLCPCB....just wanted to figure out what the issue is with this pcb in the meantime. Question....do you (or anyone here) know if the relay should kick on even when the L/R amplifier pcbs are not in circuit?
@jayfree relay PCB's arrived. Thanks for making this design available and so easy to acquire! Plan is to migrate as many good components over as possible, so prepped a sectioned container to put the resistors in as I remove them from the legacy pcb. Also transposed the resistor ID's onto the the schematic and attaching here in case others are looking for that. Time to start desoldering!
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Thanks. I may be confused still. Take TR702 for example. In the Yamaha schematic, it's a 2sb544 which has a pinout of 1=b, 2=c, 3=e. Now compare that to your schematic where the pinout of TR702 is 1=e, 2=c, 3=b. They don't match. I guess I could go through and compare both schematics to ensure the transistors i'm using match the orientation of the pinouts in your schematic, but it would just a lot quicker to see the list of transistors you used. Would you mind sharing that?
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This is perfect. Thank-you!!!!