• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

QRX-9001 need help finding an Omron relay

PatA

PatA

Super Member
I've been working on the quad board. got all the solder pass throughs reworked and replaced electrolytic capacitors, original looked good, but I had replacements. When I started on the pass throughs, I left the relay on the board, (RL02), a stupid as I damaged the cover with my soldering iron. It didn't perforate it, I am worried that it might be curved inward far enough to interfere with the contacts. I checked through my spare parts for a cover, but I don't have one, so I figured, why not just order a new one. I cannot find this thing, and frankly I have a ton of trouble every time I try to find any kind of relay. It's a type MH4P, the part number may be something like MH4P-0-24VDC. Can anyone help me with the part number? Thanks.
 
Register to hide this ad
That's a unique Omron part number. Are you sure it's an Omron relay? It's not listed on Omron's website. Can you post a picture of the relay and the relay pin configuration?

Melting the cover a little won't hurt the operation of the relay. The cover just keeps the contact clean and protected.

- Pete
 
Hey Pete, thanks for the reply, here's some pics.
 

Attachments

  • DSCN5991.jpg
    DSCN5991.jpg
    73 KB · Views: 61
  • DSCN5992.jpg
    DSCN5992.jpg
    42 KB · Views: 52
PatA

Could this be it. Coil resistance 430 ohms? Any markings on the coil?

R16-4PDT diagram (thumbnail)
R16-17D3-24 4PDT 24VDC coil
R16-17D5-24 older terminal 24VDC coil 5A contacts


Possibly NTE substitute
 

Attachments

  • Relay3.jpg
    Relay3.jpg
    4.3 KB · Views: 23
sui-san said:
PatA

Could this be it. Coil resistance 430 ohms? Any markings on the coil?

R16-4PDT diagram (thumbnail)
R16-17D3-24 4PDT 24VDC coil
R16-17D5-24 older terminal 24VDC coil 5A contacts


Possibly NTE substitute
Click to expand...

Weird that it's so tough to find, can't tell what coil resistance is. I just reuse it, thanks for the help guys.
 

Attachments

  • DSCN5994.jpg
    DSCN5994.jpg
    66.8 KB · Views: 44
  • DSCN5997.jpg
    DSCN5997.jpg
    40.4 KB · Views: 34
That is a weird one. Different design than any other relay I've seen in a Sansui. You can measure the coil resistance with an ohmmeter. Does it have three sets of contacts? If so, you may be able to replace it with the MY3 relay used in the 9090/8080DB models.

- Pete
 
Hey Pete, there is a duh moment, I have a DMM, why not just measure resistance, man I'm dumb sometimes! Resistance measures 1.2k ohms, 1200 ohms? Is that right or am I making a mistake? Measurement taken with dial set at 2K.
 
Forgot to add, it has two sets of moving points that move to make contact with one set of two stationary points or the other, hope that makes sense. Maybe this is used as a switch that routes signal through a set of pins determined by which points are activated. The relay is on the 4 channel selector board, the schematic and parts list shows it. I wish I could figure out how to attach a part of the service manual.
 
You can compare those normally closed contacts (shown in your pic) and the normally open ones and the remaining ones i can't see in your photo against the pin #'s and the diagram in post above. It looks like it could be a 4PDT relay. It appears that there were 14 solder connections to the relay.

sui-san
 
sui-san said:
You can compare those normally closed contacts (shown in your pic) and the normally open ones and the remaining ones i can't see in your photo against the pin #'s and the diagram in post above. It looks like it could be a 4PDT relay. It appears that there were 14 solder connections to the relay.

sui-san
Click to expand...

There are 14 solder connections and I want to double check, but I think your illustration is accurate as far the pin numbers.
 
if the coil isn't dead, and there is no mechanical obstruction to the contact assembly, its probably ok to use. its tricky to substitute this relay for another because of the pinout. Since there is little room to stuff a relay elsewhere in the machine it makes it tricky to sub out.

If you're never going to use the 2 channel only functionality, you can always just bypass the relay for 4 channel operation only. Its job is to switch the audio path through the decoder boards depending on the position of the speaker switch. You can see it switch when changing the speaker mode from 2 channel to 4 channel.
 
PatA

Is this the schematic you were looking at?
 

Attachments

  • QRX123.jpg
    QRX123.jpg
    120.6 KB · Views: 26
  • Image7.jpg
    Image7.jpg
    47.8 KB · Views: 18
sui-san said:
PatA

Is this the schematic you were looking at?
Click to expand...

Yep, that's it, I'm using the board diagram so I can locate my solder points. Check the parts list below the diagram, it shows that MH4P part number. If I'd just removed it from the board in the first place, I wouldn't have this problem! It should be OK to re-use, appreciate all the help.
 
channel ops

PatA said:
Yep, that's it, I'm using the board diagram so I can locate my solder points. Check the parts list below the diagram, it shows that MH4P part number. If I'd just removed it from the board in the first place, I wouldn't have this problem! It should be OK to re-use, appreciate all the help.
Click to expand...

If I recall, the guy {Quadbob} always disables the 2 channel operation on this receiver, appears it overloads something in the design.
If I were you and keeping the unit I would PM him. He also has a website, Google it.
Casey
 
nosirrah said:
If I recall, the guy {Quadbob} always disables the 2 channel operation on this receiver, appears it overloads something in the design.
If I were you and keeping the unit I would PM him. He also has a website, Google it.
Casey
Click to expand...

QB refers to the x2 two channel mode. This bridges the front and rear amplifiers to make the receiver into a 120wpc 2 channel beast. The only problem is by bridging the amps you reduce the load capability to 8 ohms minimum. Use 4 ohm speakers and POOF! Unless the driver cards are up to snuff the system is a little unstable - which is why most disable it.
 
another possibility is to measure the footprint of the relay and find one with the same footprint and plastic cover and just swap the plastic covers.
 
OK, I got the quad selection board done, I just reused the relay I that I could'nt find. The receiver has other issues, I'm trying to pick them off one by one. These are issues that I'm not in over my head on, at least not yet. The volume pot is really sloppy on it. It's the 250k ohmx4 pot, part number is 1060450, according to the SM. The shaft can be rotated beyond the stops, and doing so causes the left channel meter to swing wildly. I only have a strong left channel and a weak right, but the right channel meter will occasionally jump as the shaft on the volume pot is wiggled. So I want to replace it and run a test to see what happens. Will I be able to source one somewhere or will I need to search for a used one? Thanks.
 
You must log in or register to reply here.
Back
Top Bottom