Is it possible to adjust the tuner pot to get all FM channels. I bought a JVC RC M70 from Japan and I have all the AM channels and only about half of FM channels. When it original came to me, I had all AM channels and no FM channels. I opened the box and carefully adjusted the tuner pots and was only able to get a few FM channels. Has anybody have any experience with this issue?
Japanese Victor RC-M70 Tuner adjustments
- Thread starter FRizzo17
- Start date
You can buy Frequency extenders for Japanese cars. Frequency Converter Antenna Radio FM Band Expander 88-108MHz for Japanese Car
Someone did post on here with success
boomboxery.com
Someone did post on here with success
FM radio solution for Ghettoblasters from Japanese market
I don’t know, if such a solution already was posted. I think, a lot of people which have imported boomboxes directly from Japan, are annoyed that they cannot receive FM radio stations outside of Japan. Many early boomboxes (end of 70ies, start of 80ies), that were produced for Japanes market...
boomboxery.com
The Japanese tuner only has 14mhz bandwidth, the USA spec tuner has 20mhz bandwidth. There are circuitry differences and you aren't going to convert the Japanese one to USA one by randomly twisting some cans and pots. Even the USA service manual does not cover adjustments on tuner alignment. Good thing is that USA M70's are fairly plentiful, although prices have been going up so it's not nearly as affordable as before. But the following is an option:
boomboxery.com
Poor Mans M75 -- How To
So some of you guys with Japanese M70's that is wishing you were able to listen to FM radio beyond 88 - 90 mhz.... Listen up. Here is how it's done. You will need........ (1) A USA or Euro tuner from a donor M70 (2) A USA or Euro top plate from a donor M70 (3) A USA or Euro tuner dial (the...
boomboxery.com
That was me. It is quite easy and inexpensive. And the outside of the boombox stays in original status. To use it, you then just need to calculate the frequency.
For example if you build in a 16MHz extender and you would like to listen to an FM station at 100Mhz, then you adjust the dial to 100Mhz - 16Mhz = 84Mhz.
Extenders are available with 16Mhz, 18Mhz or 20Mhz.
I was completely confused with the way it's described in the listing. It makes sense that all you are doing is squashing a wider frequency bandwidth into the existing scale. Which means you are tuning blind but you can figure out which station is which anyway. You could use a sticker with the revised frequency range over the top of the Japanese one.
Those extenders /converters are not squashing the frequency. They are just shifting the received FM frequency (from antenna) down for a specified value. For example in a 16Mhz extender, the build in quartz chip moves the FM frequency 16MHz lower.
That means, for a device with Japanese FM frequency from 76...90MHz with a 16MHz converter you can receive the range from 82...106MHz.
With a 14MHz converter it would be 80...104MHz and with 18MHz it is 84...108MHz.
If your favorite radio station for example is transmits at 95.8MHz, then with a built in 16MHz converter you tune your Japanese radio to 79.8MHz (95.8MHz minus 16MHz).
Sorry, probably my calculator was out of order 
It should be:
That means, for a device with Japanese FM frequency from 76...90MHz with a 16MHz converter you can receive the range from 92...106MHz.
With a 14MHz converter it would be 90...104MHz and with 18MHz it is 94...108MHz.
It should be:
That means, for a device with Japanese FM frequency from 76...90MHz with a 16MHz converter you can receive the range from 92...106MHz.
With a 14MHz converter it would be 90...104MHz and with 18MHz it is 94...108MHz.
C
Can you confirm that you lose the bottom end scale because that's not how they are advertised? You would have to confirm with another radio at a station below the threshold of 92? Then see if you can pick up that station on the Japanese set?Sorry, probably my calculator was out of order
It should be:
That means, for a device with Japanese FM frequency from 76...90MHz with a 16MHz converter you can receive the range from 92...106MHz.
With a 14MHz converter it would be 90...104MHz and with 18MHz it is 94...108MHz.
They are advertising to cover the complete range from 87.5MHz to 108MHz with their converters. But this is not posiible. Why?
The reason is, that the Japanese FM frequency band is smaller then the frequency band in the rest of the world.
In Japan with 76...90MHz you have a range of 14MHz. In Europe with 87.5...108MHz you have a range of 20.5MHz. So, when you use a converter, you have to decide, which FM area is more important for you, lower or upper. If you want the area starting at 90MHz, you take a 14MHz converter (90...104MHz). If you want the area at max. 108MHz, you take a 18MHz converter (94...108MHz).
I personally took the compromise with a 16MHz converter. So from 87.5...90MHz I can receive just with the built in tuner. From 90...92MHz I have a gap. From 92...106MHz I can receive with the help of the converter. From 106...108MHz I have a gap.
The reason is, that the Japanese FM frequency band is smaller then the frequency band in the rest of the world.
In Japan with 76...90MHz you have a range of 14MHz. In Europe with 87.5...108MHz you have a range of 20.5MHz. So, when you use a converter, you have to decide, which FM area is more important for you, lower or upper. If you want the area starting at 90MHz, you take a 14MHz converter (90...104MHz). If you want the area at max. 108MHz, you take a 18MHz converter (94...108MHz).
I personally took the compromise with a 16MHz converter. So from 87.5...90MHz I can receive just with the built in tuner. From 90...92MHz I have a gap. From 92...106MHz I can receive with the help of the converter. From 106...108MHz I have a gap.
No, as the bottom end is not covered by the expander, all signals <90MHz will be passed through.That means, for example a station at 88.8MHz can be received by original tuner, with built in expander. No bypass needed.