Can I use MJL0281A & MJL0302A in place of Sanken FN1016 & FP1016 in my Rotel RB-991
Any concerns with this substitution? I have 10 pairs of these devices to sub in. They will physically fit on to the heatsink with minimal adjustment.
The original bias is for 7mV (across its 0.22 emitter resistors = 32 mA). I probably have to adjust to ?
This amp is rated for 200W/Ch.
The driver devices are 2SB817/2SD1047 are rugged and they are sometimes that are found as output devices in some amps (i.e. older ROTEL Amps)
The schematic says it uses Sanken 2SA1492 & 2SC3856 output devices but I got the dreaded FP1016 & FN1016 in its place.
Are these devices equivalent?
Any help would be appreciated!
Any concerns with this substitution? I have 10 pairs of these devices to sub in. They will physically fit on to the heatsink with minimal adjustment.
The original bias is for 7mV (across its 0.22 emitter resistors = 32 mA). I probably have to adjust to ?
This amp is rated for 200W/Ch.
The driver devices are 2SB817/2SD1047 are rugged and they are sometimes that are found as output devices in some amps (i.e. older ROTEL Amps)
The schematic says it uses Sanken 2SA1492 & 2SC3856 output devices but I got the dreaded FP1016 & FN1016 in its place.
Are these devices equivalent?
Any help would be appreciated!
I have one blown FN1016 and a blown input trans. 2SA1016 and a few blown diodes and a resistor that out of spec.
I am just disappointed that a 200W/300W into 8/4 ohms use these 5 pairs of 70W 8A devices (FP1016/FN1016)!
The driver stage uses higher current devices (2SB817/2SD1047)!!!!!
Is it really equivalent to a 2SB1587/2SD2438????
FN/FP1016: are they really equivalent to 2SA1492/2SC3856 as Rotel uses either unit as interchangeable in the RB991
How can a 70W 8A device be equivalent to a 130W 15A device as used in the 991???
I am just disappointed that a 200W/300W into 8/4 ohms use these 5 pairs of 70W 8A devices (FP1016/FN1016)!
The driver stage uses higher current devices (2SB817/2SD1047)!!!!!
Is it really equivalent to a 2SB1587/2SD2438????
FN/FP1016: are they really equivalent to 2SA1492/2SC3856 as Rotel uses either unit as interchangeable in the RB991
How can a 70W 8A device be equivalent to a 130W 15A device as used in the 991???
Have you owned this amp from new? It sounds like some idiot has repaired it at some point in the past, and used the wrong transistors.
If the schematic says that it should be using 2SA1492 & 2SC3856 i'd assume thats what should be in there. As you say in the other thread, the Aiwa house devices sound like darlingtons, and this would fit my expectations having serviced a few Aiwa stereo systems.
I think the MJL0281/0302 will work but you will undoubtedly have to alter the bias. You will also need a 'scope as suggested to make sure there is no oscillation, but from what I remember about the 2 Rotel schematic's i've seen, they tend to be pretty well compensated.
If the schematic says that it should be using 2SA1492 & 2SC3856 i'd assume thats what should be in there. As you say in the other thread, the Aiwa house devices sound like darlingtons, and this would fit my expectations having serviced a few Aiwa stereo systems.
I think the MJL0281/0302 will work but you will undoubtedly have to alter the bias. You will also need a 'scope as suggested to make sure there is no oscillation, but from what I remember about the 2 Rotel schematic's i've seen, they tend to be pretty well compensated.
I would more likely say the Rotel guy you spoke to hasn't a clue what he's talking about!
edit: I've seen this service manual myself. There is no way they would substitute darlingtons in there. Someone has done this by mistake.
My hunch is on my original theory, someone else has repaired the amp and used the wrong devices, possibly misled by Rotel's service department.
edit: I've seen this service manual myself. There is no way they would substitute darlingtons in there. Someone has done this by mistake.
My hunch is on my original theory, someone else has repaired the amp and used the wrong devices, possibly misled by Rotel's service department.
Here is a link to the RB991 schematic:
http://www.zero-distortion.com/downlaod/x1.htm
Can someone comment on the use of the FP/FN1016 in this circuit instead of the 2SA1492 & 2SC3856.
Assuming if it is a Darlington.
SO is it possible to drop in a MJL0302A & MJL3281A.
Any help would be appreciated.
Thanks
http://www.zero-distortion.com/downlaod/x1.htm
Can someone comment on the use of the FP/FN1016 in this circuit instead of the 2SA1492 & 2SC3856.
Assuming if it is a Darlington.
SO is it possible to drop in a MJL0302A & MJL3281A.
Any help would be appreciated.
Thanks
Another guess would be that fp1016 for Rotel are different...
The only way to find out would be measuring the Vbe on these devices when amp is turned on, immediately showing if these are darlingtons or not.
How do the cases look like ? MT100 or FM100 ? The FM100 looks more like a TO220, the MT100 is well known as the TO3P.
The 2SB1587 has a completely different case than 2SC3856...
The link does not work for me... (server offline ?)
Mike
The only way to find out would be measuring the Vbe on these devices when amp is turned on, immediately showing if these are darlingtons or not.
How do the cases look like ? MT100 or FM100 ? The FM100 looks more like a TO220, the MT100 is well known as the TO3P.
The 2SB1587 has a completely different case than 2SC3856...
The link does not work for me... (server offline ?)
Mike
The FP/FN1016 case unfortunelately looks like the 2SB1587.
So this is more ammo that to the fact it is like the Darlington-based 2SB1587.
With this Darlington on the output with a 2SB817 & 2SD1047 as the "Darlington drivers". Is this kosher and do they call this a triple Darlington configuration?
Will this work properly versus just having the 2SB817 & 2SD1047 drive the 2SA1492/2SC3856 as shown on schematic.
So this is more ammo that to the fact it is like the Darlington-based 2SB1587.
With this Darlington on the output with a 2SB817 & 2SD1047 as the "Darlington drivers". Is this kosher and do they call this a triple Darlington configuration?
Will this work properly versus just having the 2SB817 & 2SD1047 drive the 2SA1492/2SC3856 as shown on schematic.
The link works now for the RB-991 service manual.
http://www.zero-distortion.com/downlaod/extra/schemati/rb_991_schematic.pdf
Have a look and let me know if this Darlington-based (?) Output Devices (5 pairs) FP/FN1016 will work in the place of the stated devices (5 pairs) of the 2SA1492/2SC3856's.
Any comments will be helpful.
Thanks in advance.
http://www.zero-distortion.com/downlaod/extra/schemati/rb_991_schematic.pdf
Have a look and let me know if this Darlington-based (?) Output Devices (5 pairs) FP/FN1016 will work in the place of the stated devices (5 pairs) of the 2SA1492/2SC3856's.
Any comments will be helpful.
Thanks in advance.
I appreciate your help as you can see why I am confused.
So the situation is one of the following:
1) I believe that these devices are misapplied in this case if they are Darlingtons and put in by someone who is misinformed.
2) Is this designation of FP1016/FN1016 another (Aiwa type) OEM designation that Sanken does for all their OEM transistors that are unique to one product (far-fetched as it will cause confusion)
3) Rotel designed it to be compatible with Darlingtons & standard bipolars
Any other scenarios?
I will measure them to see the Vbe voltage across the base & emitter. I use a current limiter (a light bulb in series with the AC line to limit current to 0.5A (110VAC with 60 Watt light bulb).
So a darlington will measure 1.2 V @ min Ic in this case probably in the mA range with no load and the Bipolar will measure 0.6V at the same range.
These are from the graphs of Vbe vs IC and temperature. I assumed the current will be well under 1 Amp with no load.
I assume because there is 2 transistors in a Darlington.
I will measure and let you know.
Thanks for your help.
Dan
So the situation is one of the following:
1) I believe that these devices are misapplied in this case if they are Darlingtons and put in by someone who is misinformed.
2) Is this designation of FP1016/FN1016 another (Aiwa type) OEM designation that Sanken does for all their OEM transistors that are unique to one product (far-fetched as it will cause confusion)
3) Rotel designed it to be compatible with Darlingtons & standard bipolars
Any other scenarios?
I will measure them to see the Vbe voltage across the base & emitter. I use a current limiter (a light bulb in series with the AC line to limit current to 0.5A (110VAC with 60 Watt light bulb).
So a darlington will measure 1.2 V @ min Ic in this case probably in the mA range with no load and the Bipolar will measure 0.6V at the same range.
These are from the graphs of Vbe vs IC and temperature. I assumed the current will be well under 1 Amp with no load.
I assume because there is 2 transistors in a Darlington.
I will measure and let you know.
Thanks for your help.
Dan
I couldn't measure in circuit since I am missing the whole front end plus some rail diode. The voltage across the Base and emitter was varying all the time.
I measure a known good PNP out of the circuit and it measures a voltage drop of 0.55 V across the B & E using the diode mode.
Does this indicate a Bipolar as I thought the Darlington would be double that because of the 2 junctions of the dual transistor.
Let me know.
I will research the net in the meantime.
What are the characteristics of a Darlington outside of an active circuit?
Thanks again
I measure a known good PNP out of the circuit and it measures a voltage drop of 0.55 V across the B & E using the diode mode.
Does this indicate a Bipolar as I thought the Darlington would be double that because of the 2 junctions of the dual transistor.
Let me know.
I will research the net in the meantime.
What are the characteristics of a Darlington outside of an active circuit?
Thanks again
Yes I did buy it on EBay. It is in good shape and all the PS voltages are right except for the 8 failed1N4148, 2 out of spec resistors (R613/614) and 1 bad FN1016 and 4 bad 2SA1016 and 3 bad 2SC2362's.
It looks one channel had a bad output device (Q639) with a bad input transistor (Q607).
The other channel had a short from the R663 (10 ohm) to the standoff that holds the circuit board away from the heatsink. A portion of the tracing is missing and the brass standoff is scorched. A screw was missing on the standoff and the board shifted enough to short out. This side has almost has all the input transistors as well 4 transistors in the predriver stage shorted but no output devices damaged.
With the light bulb in the circuit as a current limiter the light is barely on. Turn power and it is bright for a second and slowly dims out to a slight illumination. I have to turn the lights off to see the glow. So the outputs are good. Under load it may be a problem.
Thanks again
It looks one channel had a bad output device (Q639) with a bad input transistor (Q607).
The other channel had a short from the R663 (10 ohm) to the standoff that holds the circuit board away from the heatsink. A portion of the tracing is missing and the brass standoff is scorched. A screw was missing on the standoff and the board shifted enough to short out. This side has almost has all the input transistors as well 4 transistors in the predriver stage shorted but no output devices damaged.
With the light bulb in the circuit as a current limiter the light is barely on. Turn power and it is bright for a second and slowly dims out to a slight illumination. I have to turn the lights off to see the glow. So the outputs are good. Under load it may be a problem.
Thanks again
So this "Darlington" FP1016 measures like a Bipolar Device.
I am assuming that a Darlington measures 1.2-1.4V across the emitter and base. Is this correct?
What I found with a FP1016 out of the circuit is as follows:
Using multimeter diode mode it measure 0.589V with + on E & - on B.
It measures 0.560 with + on C and - on B.
Its open for the other 4 measurements.
This measures like a standard Bipolar.
I have a feeling that Sanken named these FP1016 & FN1016 as the designation for generic OEM usage.
I am assuming that a Darlington measures 1.2-1.4V across the emitter and base. Is this correct?
What I found with a FP1016 out of the circuit is as follows:
Using multimeter diode mode it measure 0.589V with + on E & - on B.
It measures 0.560 with + on C and - on B.
Its open for the other 4 measurements.
This measures like a standard Bipolar.
I have a feeling that Sanken named these FP1016 & FN1016 as the designation for generic OEM usage.
dtm1962 said:
What do you mean ? Full voltage drop or zero voltage drop ?
Yes, ~0.6v indicate non darlington.
Can you confirm that you have 5 x TO220 like cases and one TO3P case mounted to the heatsinks ?
There is no way how a darlington output device should fit here.
I guess you have to order spare parts drom Rotel...
Mike
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