Identiify this RF Modulator part

[SmakyTaky]

I recently acquired a hvc-gpu-gpm-02 famicom from Japan. After hooking it up to my TV on channel 95 video was working fine (for an RF connection). However, noise and a local radio station was heard instead of famicoms audio. I tried several ways to fix it, changing to channel 96, using a quality coax cable with an adapter but nothing worked.

I tried to adjust the variable cap? (is it a cap?) on the RF module but found that no matter how many turns I did it changed nothing. I was expecting that after a few turns the image and audio would go away as I was tunning it to a different band. However, I kept turning for several minutes and it change nothing. I was expecting to get to a point where the component would not let me go further, as it did not happen and the image and sound has no change it seems to me this part (labeled T1 on the RF Board) might be broken.

Does anyone knows the specs and part number for this thing so I can try to get a replacement one?

Thanks.

[FAMICOM_87]

Just desolder it and replace, but do you consider a AV MOD?there is very nice revursable mods out here

[SmakyTaky]

Thanks, this is my plan. To remove this part and replace it. However, I am not sure what are the specs of this part. Well not even sure what type of part it is.

[FAMICOM_87]

this is the part name https://www.rf-microwave.com/en/tunable-rf-coils/208/
but can not help with the parameters what is the diapasone of uH 

[FAMICOM_87]

better do this MOD it is clean and 100% reversible ,for your model exactly
 https://www.youtube.com/watch?v=ky8rFPbzGMU

[SmakyTaky]

Thank you so much. I am planning to do that exact mod as you mentioned is not disruptive. However, I also want to fix the RF output. So thanks again for the info.

[SmakyTaky]

this is the part name https://www.rf-microwave.com/en/tunable-rf-coils/208/
but can not help with the parameters what is the diapasone of uH 

Not sure what you measn by diapasone of UH.. is that something I can read from the part somewhere?

[SmakyTaky]

looking at the coil it is labeled "698 YP" does this help identify the specs?

[FAMICOM_87]

No problem, just do the MOD 
By the way I am not sure what kind of specs have to be this tunable coil , but μH means microhenry, that is a measurement unit for inductions in coils.
BTW you coil may be not broken only the thread is damaged, so you can fix this with a  slow curing glue . find a compatible japan NTSC TV. One drop of a glue inside the coil hole and then put the core and tune it, when you got the good sound wait a glue to cure and never touch the coil again ! 

BTW
I have a multi-region TV from mid 90's it can do NTSC and PAL, but only JAPAN NTSC and PAL have sound via RF , just like like you, but the opposite. I do not have any sound from USA NTSC consoles via RF.
this may be helpful next time, but unfortunately the model in the video is the early one, but still informative take a look
https://www.youtube.com/watch?v=RVyFEMg0Kpg&t
 

[SmakyTaky]

Thanks for the explanation... My TV although not Japanese do have channel 95 and 96 (I use it for other famicoms and Super Famicoms consoles I have). When properly tuned they show a "clear" image (as much as RF can give) and very clear sound.

However with this coil, no matter how many turns I do to the coil tha image and audio has no change... if I understood properly the slow turning glue migh help get enough friction with the thread to let it actually turn? Is that it? By core what do you mean.. the coild looks complete, nothing has came off.

Thanks for the link to the video.. this is the one that gave me the idea to try to adjust the coil in the first place. I have done this with a Colecovision and a Superfamicom and it worked just fine - although I simply adjusted the superfamicom to channel 95.

[FAMICOM_87]

You have a core with treath inside this coil, it is like a screw, you can take it out.
You may be destroyed the plastic treats on the coil side, it happens some times. One of my famicoms is the same 1989 revision like yours and in my case to get a clear sound I think by unscrueing this core by maximum, so now it is nearly half out side and I drop one drop glue to secure it, because it wobbles from not enough threat to stay by it's own. This is my case, so try.

[SmakyTaky]

Thanks for the advice.. I will try your suggestion.

[SmakyTaky]

Sorry for keep asking.. I do see the thread inside the component... however I have no clue on how could I pull it out. I do not want to destroy it.

Are there any common values these RF tunable coild have that may be used in RF modulators... I have been searching on the web and this seems to be a 7x7mm tunable coil. Not sure if this together with the fact that this is supposed to help tune the circuit for RF modulation on japanese channels 95/96 (that is 91.25 and 97.25 MHz, resoectively) may be of use to try to identfy possible replacement parts.
 

[FAMICOM_87]

There should be threat. If you do jot see it or can not unscrie the core, you defenetly destroyed it. Try to pull out the core by unscruing it and the console up side down to drop it. Try to find this part from a broken famiclone, may be it will not be the exact same parameters if the famiclone is PAL, but in NTSC clone shold be the same coil.
But why ti hassel with this, just try the AV MOD.

[SmakyTaky]

I have already ordered the parts to do the AV MOD. On the stubborness part, I just want to have the console work as close as it was once it was released.

I removed the couil from the modulator to have more room to jiggle with it. I though that after removinfg it, there would be no signal comming from the modulator, however, after I tested it, the video signal is being shown with no issues and it is only the audio part that is missing (only static and from time to time some interference from a local radio station is heard). Seems the RF Coil is only affecting the sound signal and not the video at all.

Are there any schematics for the RF modulator available somewhere? I have been searching on the web with no luck so far.

The modulator has a sticker that shows HVC-VCCI 033750A-A... but was unlucky finding any reference to it.