"Does R413 need to match the coil resistance of the relay? "
Of course not.
The resistor is adjusted until the voltage drop across the relay is correct. A different relay will require a different resistor. Use the resistance of the new relay to determine the amperage at nominal voltage. Subtract nominal coil voltage from supply voltage. Divide difference in voltage by new relay amperage to determine new resistor value (Ohms law stuff).
Of course not.
The resistor is adjusted until the voltage drop across the relay is correct. A different relay will require a different resistor. Use the resistance of the new relay to determine the amperage at nominal voltage. Subtract nominal coil voltage from supply voltage. Divide difference in voltage by new relay amperage to determine new resistor value (Ohms law stuff).
2200 relay replacement
swinnea, I looked up the part number for the relay you gave me and I noticed that the contacts were a form "c" closed but when I compaired it with the takio unit it states it contacts are of the "a" type. I then looked at the parts list on the nad 2200 PDF and showed the original part being a taiko Rxs 2405U not Pxs 2405U, do you think this is a misprint and is there a difference between a NAD 2200 and a NAD 2200PE?
And is there anybody on the forum that can tell me why the one company recommends replacing the IC buffers and does anybody have any reference material on how to modifiy the power supplyto make it better.
swinnea, I looked up the part number for the relay you gave me and I noticed that the contacts were a form "c" closed but when I compaired it with the takio unit it states it contacts are of the "a" type. I then looked at the parts list on the nad 2200 PDF and showed the original part being a taiko Rxs 2405U not Pxs 2405U, do you think this is a misprint and is there a difference between a NAD 2200 and a NAD 2200PE?
And is there anybody on the forum that can tell me why the one company recommends replacing the IC buffers and does anybody have any reference material on how to modifiy the power supplyto make it better.
thanks swinnea, the IMO SRKU-1CT-SL-24VDC looks very good as a replacement for the old Taiko relay. it's almost a drop-in replacement, looks like I will need to trim the DPDT extra pin # 3 (as shown in Taiko PX-2405 datasheet). I don't see any other pins to be trimmed, as you mentioned a couple. Have you tried your NAD amp with the IMO part installed and all is working ok ?
I also need to replace the relays in my 2200 and would love to hear back from anyone who has tried that IMO relay. Were you able to mount it to the PCB? Did you need to change any resistors?
If the IMO relay does not work, then it appears the Omron relay would require off-board mounting with wires run to the PCB. Is that correct?
My original relays are working at the moment after cleaning the contacts, but I'd like to get new relays ready to install.
Thanks for your help!
AM.
If the IMO relay does not work, then it appears the Omron relay would require off-board mounting with wires run to the PCB. Is that correct?
My original relays are working at the moment after cleaning the contacts, but I'd like to get new relays ready to install.
Thanks for your help!
AM.
If anyone is still interested in this subject:
I replaced a pair of original Taiko relays in a NAD 2200 with the above mentioned IMO relays. The taiko vs. IMO footprint is almost identical; I just had to enlarge four holes in the PCB to accommodate two slightly larger pins on each IMO.
The IMOs take a bit more current to solidly toggle so I replaced R413 with a 240 ohm, 2 watt carbon comp resistor. Each relay now has a solid 22VDC across their coils, it is all working marvellously, and they make a very nice "click" when they energize.
These are definitely an excellent choice for replacement relays in this amp. Thanks for the clue, swinnea.
I replaced a pair of original Taiko relays in a NAD 2200 with the above mentioned IMO relays. The taiko vs. IMO footprint is almost identical; I just had to enlarge four holes in the PCB to accommodate two slightly larger pins on each IMO.
The IMOs take a bit more current to solidly toggle so I replaced R413 with a 240 ohm, 2 watt carbon comp resistor. Each relay now has a solid 22VDC across their coils, it is all working marvellously, and they make a very nice "click" when they energize.
These are definitely an excellent choice for replacement relays in this amp. Thanks for the clue, swinnea.
Hello!
I am working on two NAD 2700 THX, as i understand they are almost the same design in the 2xxx series..
Guygo, did it work out well over time with the lower resistance on the R413?
I am thinking about the increase in current that occurs from lowered resistance. There is no risk for the circuit managing the relays to go bad from the higher current?
/Niklas
I am working on two NAD 2700 THX, as i understand they are almost the same design in the 2xxx series..
Guygo, did it work out well over time with the lower resistance on the R413?
I am thinking about the increase in current that occurs from lowered resistance. There is no risk for the circuit managing the relays to go bad from the higher current?
/Niklas
I am too in a similar predicament! I am trying revive a NAD 2155 & the output relay of this needs replacement. However, the service manual gives only the part No. which is 81-619 & no other details as to it's voltage & current ratings!
Have anyone of you guys replaced this relay, on this particular model & if so could I possibly have the replacement manufacturer part No. for this unit please? What voltage/ current rating is this relay?
Thanks.
Have anyone of you guys replaced this relay, on this particular model & if so could I possibly have the replacement manufacturer part No. for this unit please? What voltage/ current rating is this relay?
Thanks.
IMO relay for the 2200
nibjo - The IMO relays with a bit more juice are working very nicely. No failures, no complaints.
teleman - break out the voltmeter and measure the voltage across the relay coil. If it's close to 24VDC, the relay is a 24V device just like the above IMO relays are. In the 2200 There are two 24VDC relays in series being driven from 44VDC. In the 2155 there is one relay for both channels being driven from IC801 (the TA7317) with the coil current being supplied by R807 (680 ohm, 2 watt). As noted above, replacements may need a bit more current to kick in, but that would just mean changing the resistor that feeds them.
I am of the opinion that the mechanical footprint is the most important criteria. The electronics can be fudged with, but tearing up the PCB to accommodate a replacement is the last thing you want to do. Take a look at the footprint of the existing relay in the 2200 and compare it to the IMO's. I bet they are close to identical. If so - and the kick voltage in the unit is close to 24VDC, the IMO is what you need to do the job. If not, find something with the correct footprint first, then figure out how to make it kick.
nibjo - The IMO relays with a bit more juice are working very nicely. No failures, no complaints.
teleman - break out the voltmeter and measure the voltage across the relay coil. If it's close to 24VDC, the relay is a 24V device just like the above IMO relays are. In the 2200 There are two 24VDC relays in series being driven from 44VDC. In the 2155 there is one relay for both channels being driven from IC801 (the TA7317) with the coil current being supplied by R807 (680 ohm, 2 watt). As noted above, replacements may need a bit more current to kick in, but that would just mean changing the resistor that feeds them.
I am of the opinion that the mechanical footprint is the most important criteria. The electronics can be fudged with, but tearing up the PCB to accommodate a replacement is the last thing you want to do. Take a look at the footprint of the existing relay in the 2200 and compare it to the IMO's. I bet they are close to identical. If so - and the kick voltage in the unit is close to 24VDC, the IMO is what you need to do the job. If not, find something with the correct footprint first, then figure out how to make it kick.
Thank you guygo for your invaluable info! Yes, I completely agree & you're absolutely right about the perils of modifying or ripping the pcb tracks in order to fit the relay or for that matter any component! I am old school when it comes to replacing parts-always the original or the closest direct replacement when this is impossible!
I will compare & measurement the pcb foot print of the relay & then try to locate a direct replacement part for it! "Finder" brand relays too can be suitable I suppose?
Cheers
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You might want to see this thread, IMHO a much better remedy.
http://www.diyaudio.com/forums/solid-state/191449-output-relays.html
Mike
http://www.diyaudio.com/forums/solid-state/191449-output-relays.html
Mike
Hi Teleman,
I just replaced the output relays in my NAD C740 with small footprint (24mm long) 24V DPST from this seller 2 Slim Power Relay 24VDC 3A DPST Non Latch Flux Resistant Aromat ALA2F24 | eBay
If that's the type you're looking for they're working really nicely.
Cheers
I just replaced the output relays in my NAD C740 with small footprint (24mm long) 24V DPST from this seller 2 Slim Power Relay 24VDC 3A DPST Non Latch Flux Resistant Aromat ALA2F24 | eBay
If that's the type you're looking for they're working really nicely.
Cheers
Thank you junior35!
The relay you have recommended & used is a DPST. Looking at the 2155 service manual, it looks like a DPDT 10 pin latching type relay in a single package! Please refer to location SO808 in the service manual. Could some one please verify this? Further, the 2155 is 55w/8 ohm while the C740 is rated @ 35w/8 ohm continuous RMS! So I wondered if this relay might not be sufficient for the 2155 due to it's higher output current or am I being over cautious? In any case I'd need a DPDT in a single package!
Thanks so much just the same since your reply has been a great help in narrowing my search!
Cheers!
The relay you have recommended & used is a DPST. Looking at the 2155 service manual, it looks like a DPDT 10 pin latching type relay in a single package! Please refer to location SO808 in the service manual. Could some one please verify this? Further, the 2155 is 55w/8 ohm while the C740 is rated @ 35w/8 ohm continuous RMS! So I wondered if this relay might not be sufficient for the 2155 due to it's higher output current or am I being over cautious? In any case I'd need a DPDT in a single package!
Thanks so much just the same since your reply has been a great help in narrowing my search!
Cheers!
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Sorry for the late reply..was distracted by other trivia! I've now ordered the relay as junior35 recommended! The thermostat too needs replacement I don't see any marking either on the device or any details given in the service manual either! guygo I still haven't tested the relay as I don't have a 24v dc supply!
Anyone who knows what temp for this thermostat is?
Thanks.
Anyone who knows what temp for this thermostat is?
Thanks.
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