Mr. Yamaha
Not so much Yamaha lately...
Looks great!
Don't know exactly from the top of my head, but it's somewhere mentioned in this thread.Mr. Yamaha,
What are those RCA input jacks and binding posts you used?
Like any other "DC Sound" ...So...... how do the majestic KG sound ???
Almost didn't recognize you Oilmaster, nice avatar
So...... how do the majestic KG sound ???
hi Spagetti, what serial number is your unit and would you please look at R147 and R149 when you are doing the driver boards? Also, is your unit US, EU or Japan?Thanks to all contributors of this amazing thread, I am working on a recently purchased B2 and I am finding so much useful information here.
Regarding the service manual, I found a very nice PDF version on www.manualslib.com, which comes in color and in high definition (~20Mb download), much better than the other available on hifiengine & co.
hi Gang, quick question regarding the B-2 driver boards, respectively the R147, R149 voltage divider:
On a US model that I have, with a later, 10k+ serial number, the actual resistors are 1k each, an even split. On the older <3k serial number units from Japan On at least two of them, the R values match the schematic (R147 =1.5k, R149 =470R)
is anyone aware of a service bulletin that accounts for this change in later models?
boards numbers are different as well
Older: NA06747
Newer: NA06811
is anyone nere aware of this change, or has noted the different (from schematic) value resistors?
hi Spagetti, what serial number is your unit and would you please look at R147 and R149 when you are doing the driver boards? Also, is your unit US, EU or Japan?
Thank you Sir!I don't think it's a big deal all together.
1) During normal operation it does not impact the bias circuit's current or voltage values, as the voltage dividier is not active while the total resistance sum remains the same. (in fact, it's not a voltage divider)
2) During start-up, when the +/-B2 power rails turn on later than the +/-B rails, then there is a minor impact due to the fact the bias circuit (fed via D112/113), since the series resistance from rail to rail will be 1kOhm higher, though that is relatively irrelevant due to R153 (33K) and VR102 (100K max) which dominate by far the DC resistance in that loop.
Frankly, the purpose/benefit of that mod escapes me.
In my European B-2 with serial no. 4027 the color codes of those resistors are as follows (R147 on top):hi Gang, quick question regarding the B-2 driver boards, respectively the R147, R149 voltage divider:
On a US model that I have, with a later, 10k+ serial number, the actual resistors are 1k each, an even split. On the older <3k serial number units from Japan On at least two of them, the R values match the schematic (R147 =1.5k, R149 =470R)
is anyone aware of a service bulletin that accounts for this change in later models?
boards numbers are different as well
Older: NA06747
Newer: NA06811
is anyone nere aware of this change, or has noted the different (from schematic) value resistors?
@Oilmaster would you happen to be aware of this change?
Thank you!In my European B-2 with serial no. 4027 the color codes of those resistors are as follows (R147 on top):
View attachment 1080395
yep, same board version as the Japan, early serial number boards I have. So It is based on early vs later unit serial numbers rather than the market region.
Yes, the blue ones. I will never forget: no silpads and no mica plates, just thermal pasteyep, same board version as the Japan, early serial number boards I have. So It is based on early vs later unit serial numbers rather than the market region.
your unit has the blue heatsinks, correct?
yep, really nice to work with. Just be mindful with the tightening.Yes, the blue ones. I will never forget: no silpads and no mica plates, just thermal paste