MR-73 Tuning Meter

hot-heater

New Member
Hello All,

I am new to the site but have followed many of your posts. I have an MR-73 I bought used when you could still buy them new. It has served me well all these years but now it's time for some payback! I've recapped it and aligned the AM section (I have the equipment to do that). The FM is still satisfactory (I can't afford the equipment to align it). The Stereo indicator blinks as the machine stabilizes. I've ordered the LDR and the driver transistor. What I really need is a tuning meter! Mine is open. The +/- signal is at the terminals but no movement. Any thoughts?

FYI The MR-73 is attached to a C27 which drives a MC 2125 and a pair of ML10Cs. Also attached is a Thorens TD 160 and B&O 6500
 
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Welcome to AK.

The meters on the MR73, 74, 77 and 78 are NOT easy to replace. You have to remove the front glas panel, the inner glass and hinge the black steel plate forward. The dial cord has to be loosened a bit and the dial pointer hinged upward so the black steel plate can pass under it. The meters for the 73, 74 and 77 are the same but are not available any more. The meter movements on the 78 are the same as the earlier models but the clear front window that goes through the rectangular hole in front is a different size. Buy the 78 center tuning meter from Mac Parts. The meters are in three pieces like a sandwich; front window, meter movement and rear plastic with printing. The pieces are held together with two screws. Separate the new and old meters and put the new 78 movement between the front and back pieces of the 73 meter.
 
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Welcome to AK.

The meters on the MR73, 74, 77 and 78 are NOT easy to replace. You have to remove the front glas panel, the inner glass and hinge the black steel plate forward. The dial cord has to be loosened a bit and the dial pointer hinged upward so the black steel plate can pass under it. The meters for the 73, 74 and 77 are the same but are not available any more. The meter movements on the 78 are the same as the earlier models but the clear front window that goes through the rectangular hole in front is a different size. Buy the 78 center tuning meter from Mac Parts. The meters are in three pieces like a sandwich; front window, meter movement and rear plastic with printing. The pieces are held together with two screws. Separate the new and old meters and put the new 78 movement between the front and back pieces of the 73 meter.

Thank you!!
 
Welcome to AK.

The meters on the MR73, 74, 77 and 78 are NOT easy to replace. You have to remove the front glas panel, the inner glass and hinge the black steel plate forward. The dial cord has to be loosened a bit and the dial pointer hinged upward so the black steel plate can pass under it. The meters for the 73, 74 and 77 are the same but are not available any more. The meter movements on the 78 are the same as the earlier models but the clear front window that goes through the rectangular hole in front is a different size. Buy the 78 center tuning meter from Mac Parts. The meters are in three pieces like a sandwich; front window, meter movement and rear plastic with printing. The pieces are held together with two screws. Separate the new and old meters and put the new 78 movement between the front and back pieces of the 73 meter.

Received the meter from McIntosh. The part that holds the meter movement was a little different but I was able to use the old clear front with the new meter movement and new back. Couple of things. I was able to loosen the old meter movement from the bottom and feed it through the tuner cables to the top and out. I reversed the procedure to put the meter back. It still didn't work. The schematic calls for 4.7K resistor across the meter terminal but I found a 1K on mine. Fooled with both but still no go. Looking carefully at the meter assembly I noticed a line along the bottom that I thought was a seam in the plastic. After careful examination I saw that it was an extremely fine (hair width) piece of wire bridging the meter terminals. I removed it and all is well. The 4.7K resistor (as noted in the schematic) provides more deflection in the pointer movement then the 1K. The thin wire might have been on the terminals to prevent static damage and/or prevent excessive movement of the pointer during handling/shipping. As I said it is extremely thin and easily overlooked so beware if you plan on changing your meter.
 
I'm glad you got it working. Based on what you said, the printing behind the meter needle now looks like an MR78, not an MR73. Luckily there isn't much difference. I needed to change the signal strength meter on my MR77 and there is three lines of text on the 78 meter rather than just numbers. I do not remember a fine wire on the meter I bought. May I ask what you paid for the meter? BTW, I sold my MR77 and MR78 and only have the digital tuner inside my MX130 now.
 
I'm glad you got it working. Based on what you said, the printing behind the meter needle now looks like an MR78, not an MR73. Luckily there isn't much difference. I needed to change the signal strength meter on my MR77 and there is three lines of text on the 78 meter rather than just numbers. I do not remember a fine wire on the meter I bought. May I ask what you paid for the meter? BTW, I sold my MR77 and MR78 and only have the digital tuner inside my MX130 now.

$10 + $8 shipping and handling.
 
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