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Hitachi HT-20s belt drive turntable

penkosey

penkosey

Well-Known Member
I just acquired this turntable for basically nothing. I'm aware that it's nothing special but it also looks to have been taken care of and has a working Shure cart on it.

It is running just too fast enough for me to want to listen to it, although the actual sound quality sounds nice. I see absolutely no way to adjust the speed, even after having taken the bottom panel off. I downloaded the manual at VinylEngine but it's very bare bones and gives no insight as to speed adjustment.

It did not have a belt and I put one on it that came from another used turntable that appeared to have the exact same platter dimensions and distance to motor pulley, but I guess it could still be not the exact right belt although it appears to fit well. Laying flat, the belt appears to be 12" and the widest point of the platter area for it looks like 7 3/4". Just posting those measurements in case they are common basic ones often seen.

The only info I've seen on this turntable is people asking why theirs is running too fast! Anyone familiar with this TT or similar models?
 
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By the way, a bunch of what I'm writing keeps getting deleted....that's what I get for trying to post from my phone. Hopefully my posting makes sense.
 
DC servo motor, there are probably adjustment pots somewhere, either below the platter near the motor, or below the deck. The problem may just be the belt your using. This table uses a 22.4 inch belt, while the most common of that era was 23.6
 
The wrong belt will definitely affect the speed. I believe a belt that's too thick will make the unit run too fast.

I don't currently own any belt drive tables. But the ones I DID have, I always had to clean the motor pulley of years of accumulated gunk - a little gunk really increases the speed.

You can always put a wrap of electric tape on the platter pulley to make it slightly larger - this will slow it down.

Usually these belt drive tables have an AC-syncronous motor that gets its speed from the 60hz AC power. Of course if your table was made for 50 hz and you run it on 60 it will run 20% fast....
 
Good suggestions. If common belts were 23.6" and I measured mine laying flat at 12", then that puts my suspect belt at pretty close to 24". A bit off from 22.4".

Question--does wrapping tape around the pulley get a bunch of sticky gunk on it?
 
Question--does wrapping tape around the pulley get a bunch of sticky gunk on it?

There is never a reason to wrap tape around the pulley. Wrapping tape(Dymo label tape with the hard backing works well) around the PLATTER is usually a last step measure if the 'table is going a little fast. I would definitely go to a reputable online dealer (turntableneedles, lpgear for example) and replace the belt. Remember, length, width, and even thickness are important.
Have another look for pitch pots. They won't necessarily be labeled, but I don't know of ANY Japanese made dc servo belt drive 'tables of that ilk that don't allow for speed adjustment.
 
I've had a couple of these cross my bench over the past few years. They're actually decent low-buck decks, and great for college kids or for people easing back into vinyl. Can't say anything really bad about them, so springing for a good quality belt is worth the time. If you get it for next to nothing, then ten bucks or less is a good karma investment, and you can probably sell it or trade it for something you need without sticking it to anyone. Good luck!
 
Thanks, guys. I do believe the donor belt is a larger one and I need the 22.4 as was pointed out above. It's funny trying to understand the circumference effects; I'd have guessed a larger belt would've made it play too slow, as opposed to too fast.
 
I would agree on the belt , i have certainly been through this with many tables ...amazing how just a little off in length or width can throw the speed off .
 
New proper size belt is on the way. I have confirmed that this corrects the speed issue by making a temporary belt out of magnetic tape from an old cassette...mine is imperfect but the music is much closer to being the right pitch.

Unfortunately I see a different problem. I see this issue when the belt is not connected, so it is not motor/belt related--

When I spin the platter, it spins freely. But I noticed when I look straight down on it, I can see a tiny amount of variation in what should be a perfect circular motion. So, looking down at the edge of the platter, I can see a slight variation in distance compared to the plinth. When I place the mat on it, this irregularity becomes glaringly obvious as I can see an even bigger "wow" shift with the contrast of the black mat and the light grey plinth.

Looking straight at the front of the turntable at eye level, I can see the platter faintly raising and lowering as it spins. I don't know of any way to "seat" the platter any more than it already sits.

I don't know if the irregularity I'm seeing looking down is due to the platter not being exactly level, or if it is an issue with the platter somehow not being centered perfectly. I have taken the aluminum platter off and set it on a flat surface, and nothing jumps out at me of it being warped. Also, I've gently felt the spindle and it does not feel bent, nor does it "give" to being pulled in any lateral direction--feels like it's mounted securely and looks perfectly vertical.

I don't know if this was just a quality control issue when it was manufactured, but it sure looks off to me more than an acceptable amount. However, the turntable also shows no signs of having been abused (I'd expect something like bent/warped parts on an obviously beat-up table....but this one looks pretty clean).
 
I'm jump starting this old thread because I just found 2 of these in local ads for very little coin. Seller did not know history.

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Both have the Shure R47 EDT. One stylus bent, one broken off. Both belts are in pieces.

Both motors run on both speeds. Platters spin a long time after given a twist. Dustcovers good. I will get belts from Gary at VOM, mount working carts, and see what I get.

Many styli available for this cart. Maybe one TT would be good dedicated to 78s.

Edit: Oops nevermind, these don't do 78. Maybe a cart swap...
 
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That RS 5T stylus definitely needs replacing. It's the equivalent of a Shure N75 stylus (for an M75 cartridge) - I think that one is the same as an N75EJ. However, I imagine the arm is quite light, so a lighter-tracking, higher-compliance stylus would be a better match. I would advise you to go for an N75ED stylus. There are plenty of aftermarket copies available but choose carefully - Jico and Tonar are reputable brands, but some vendors sell these Japanese-made styli under a different brandname.
 
Ok...thread revival. Just finished tuning one of these up half an hour ago. The pitch adjustment via VR pots is under the pcb. I cleaned the old grease out, replaced it, added a new belt and adjusted the speed via the VR. Dead on time.....in about 30 seconds effort. Compare that to the akai 005 on the bench that I cant get close after 3 days of friggin around.

Pros of the table: value...big value for $10. It sounds really really good. Another peanuts table that has 0 humm, works as intended and the tonearm plastic compound is dead silent. Really great sound. Very surprising. Reminds me of the technics manual belt slb10. Very simple captured BB bearing.. not enclosed. Semi auto works perfectly. Every once and awhile I come across a sleeper table. Id be happy with this one. M95ed hitack cart.

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I polished the lid and it looks really decent.
 
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SmileyFace - you say "The pitch adjustment via VR pots is under the pcb" my Hitachi runs slow, but i can't find the pitch adjustment, i've got the bottom off the deck, i see the motor, but otherwise i'm lost. what is the pcb and where is it?
thanks
 
analogtable said:
SmileyFace - you say "The pitch adjustment via VR pots is under the pcb" my Hitachi runs slow, but i can't find the pitch adjustment, i've got the bottom off the deck, i see the motor, but otherwise i'm lost. what is the pcb and where is it?
thanks
Click to expand...
Small pcb towards the front. You need to remove it if I recall correctly. Under the switches on the front.
 
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