It is a Sanyo Plus P55 power amp which has the Takamisawa relays. I have seen a suggestion that an Omron MY4-02-DC24 can replace the original Takamisawa MAT4B-212R 24V but before possibly spending money on two relays that may not be compatible, I thought I'd look for confirmation here.
If I order replacement Omron Relays with pins, not lugs, can anyone confirm the pinout and pin spacing will be correct?
There is are small traces of what looks to be rust inside the original relay so I believe replacement would be logical.
I cannot comprehend what I see on an Omron datasheet to compare with the diagram printed on the Takamisawa housing.
If I order replacement Omron Relays with pins, not lugs, can anyone confirm the pinout and pin spacing will be correct?
There is are small traces of what looks to be rust inside the original relay so I believe replacement would be logical.
I cannot comprehend what I see on an Omron datasheet to compare with the diagram printed on the Takamisawa housing.
Can't tell from the pics, but yours looks to be a 4PST relay whereas the OMRON is a 4PDT. Not going to drop in. If you have calipers, I'd measure the pin spacing. If no calipers, maybe if you have some .1" perf board you could check if they are on .1" centers. Otherwise they are close. Same coil voltage(24V) and omron is a 5A which is more than your 3A rated relay, so contact ok.
Thanks. I should have included a photo of the Takamisawa relay's underside which is below.
The relay's purpose is to engage/disengage both channels of speaker system A. There is a duplicate relay doing the same job for speaker system B.
I have also included a photo of the underside of an Omron MY4 02 DC24 relay I just now found courtesy of the radwell.ca website. If the pin spacing matches, could I not remove the Omron's top row of pins?
Using calipers as suggested, pin spacing of the original Takamisawa is in the vicinity of 0.13".
If an Omron's pin centers are .1", the difference is 0.03" or about .75mm. Might it be possible to modify pin spacing and/or enlarge pin holes sufficiently so that an Omron would fit once its excess pins are removed?
Takamisawa:
Omron
The relay's purpose is to engage/disengage both channels of speaker system A. There is a duplicate relay doing the same job for speaker system B.
I have also included a photo of the underside of an Omron MY4 02 DC24 relay I just now found courtesy of the radwell.ca website. If the pin spacing matches, could I not remove the Omron's top row of pins?
Using calipers as suggested, pin spacing of the original Takamisawa is in the vicinity of 0.13".
If an Omron's pin centers are .1", the difference is 0.03" or about .75mm. Might it be possible to modify pin spacing and/or enlarge pin holes sufficiently so that an Omron would fit once its excess pins are removed?
Takamisawa:
Omron
I didnt look up the omron but I believe these ice-cube control relays follow convention and if so, the top row are for the NC contacts and, spacing aside, would work fine. I'd verify on the spec sheet because you certainly don't want to have to apply power to shut off your amp.
Edit: I looked and the top row is indeed NC so short of finding a direct replacement, you can make it work
Edit: I looked and the top row is indeed NC so short of finding a direct replacement, you can make it work
Thank you for your comment and for taking the time to investigate.
I just placed an order with Digikey for two of those Omron relays. It seems that it would be less time consuming to clip off a row of pins rather than to search for a 4PST type.
As it happened, while rummaging through a parts box this evening, I came across a single MY series 24V Omron relay that I pulled from a Teac open reel deck a few years ago. At that time I suspected it was faulty and replaced it. Likely with the exact same Omron version I have just ordered. Not sure why I kept it but it served a purpose.
Having an Omron to compare pin separation against these Takamisawa relays was a bit of luck and they appear indetical.
I just placed an order with Digikey for two of those Omron relays. It seems that it would be less time consuming to clip off a row of pins rather than to search for a 4PST type.
As it happened, while rummaging through a parts box this evening, I came across a single MY series 24V Omron relay that I pulled from a Teac open reel deck a few years ago. At that time I suspected it was faulty and replaced it. Likely with the exact same Omron version I have just ordered. Not sure why I kept it but it served a purpose.
Having an Omron to compare pin separation against these Takamisawa relays was a bit of luck and they appear indetical.
I have not heard the term "flyback diode". Therefore, no, I was not planning to install one.
But @mikeAtx's post made me look at the schematic and each of the two relays has an IN4003 diode associated with it. Would this be a Sanyo factory installed flyback diode or are they for another purpose?
But @mikeAtx's post made me look at the schematic and each of the two relays has an IN4003 diode associated with it. Would this be a Sanyo factory installed flyback diode or are they for another purpose?
Yes those are the diodes we are talking about. You will not need to add one. The coil acts as an inductor. When the relay is turned off, the current wants to keep flowing and the diode gives it a path to do so. Without the diode, the voltage on the coil would increase causing the transistor driving the coil into possible breakdown.
Thanks for the explanation. One can learn new things every day. Whether one, particularly me, can remember those things is another matter.
Tomorow or the day after, I will begin replacing electrolytic capacitors. Except the four 63V - 10,000uF filter caps. Replacments are too costly. The relays should arrive later this week so once capacitors are installed, I will install those.
Tomorow or the day after, I will begin replacing electrolytic capacitors. Except the four 63V - 10,000uF filter caps. Replacments are too costly. The relays should arrive later this week so once capacitors are installed, I will install those.
They are better called free-wheel diodes, since they perform that function for the circulating current in the inductor circuit. The one's in the Sanyo circuit are exactly for this purpose. Without them the relay driver transistor will be destroyed unless it has something like a 500V rating. Even if the drivers can take the voltage, the spikes will generate considerable interference in nearby circuitry. So they are always used for DC switched relays - for a.c. an RC snubber can serve a similar function.
Capacitors are in, relays installed and the amp has so far worked properly. No intermttant right channel on speaker system A - for now anyway.
There are some adjustments described in the service manual. One of which requires a 100 watt 8 ohm resistor across + & - speaker terminals. I should have those on Tuesday.
There are some adjustments described in the service manual. One of which requires a 100 watt 8 ohm resistor across + & - speaker terminals. I should have those on Tuesday.