Hitachi TRQ-295R: a snapped belt and two kinds of screw
Deck: Hitachi TRQ-295R, made in Singapore, late seventies. £14.80 including postage, eBay, sold for spares or repairs. Symptom: motor runs, nothing moves.
The seller's description was better than most: "It sounds as if it's got life to it, but when you put the tape in and press any of the buttons it doesn't do anything." That's an honest fault report and it's also nine times out of ten a belt.
It turned up with the black slip case and nothing else so no mains lead. Not a problem as it takes 4 C cells and cells are the safer way to power up anything that's been sitting for years. Radiomuseum has these as 1977 with a question mark so I'll say late seventies and leave it there.
Battery bay clean, no green bloom on the springs which is the first thing I check on anything this age because leaked cells will cost you more than the machine's worth. Fascia scuffed to bits which I like.
Cells in. PLAY latches and stays down. The speaker gives a faint click as it powers up and I can hear the motor whirring away. The take up spindle doesn't turn and nothing moves in the window. Electronics alive, motor alive, drive not reaching the transport.
Inside
PH2 bit. 2 screws in the base plus a couple more hiding inside the battery compartment. One fought me hard enough that I wondered about threadlock, which turned out to be forty years of accumulated tar. This machine has lived somewhere with a heavy smoker in it. You can smell it the moment the case comes apart.
The belt was lying loose in the bottom of the case in two pieces. Laid out straight it's about 225mm.
The path turned out to be three points, not two. Motor pulley at the bottom, flywheel at the top, and a white nylon wheel on a sprung arm in the middle that keeps the belt clear of the casing and takes up slack as it goes. I'd assumed a simple two wheel loop before the lid came off.
The screws
Here's the half hour I'd like back. The screws from the battery compartment and the ones recessed into the case look near enough identical in the palm of your hand and they aren't. Different thread pitch entirely, one a coarse self-tapper and the other a fine machine thread. I got one into the wrong hole on reassembly felt it not seating, and spent a while convincing myself I'd cross threaded something before I lined all four up on the bench and saw it.
Nobody tells you this bit. Next time they're going on masking tape in position order.
What I fitted
A 75mm square section belt from the assortment kit which surprised me. The old belt measured about 225mm laid out straight and the usual advice is to fit something a few percent under the path length so it sits under proper tension which would have pointed at around 65mm. 75mm works out at 236mm round longer than the dead one measured.
Perished belts don't only stretch. Plenty of them shrink and go hard as the plasticiser leaves and I guess this one had. Sizing down from the old belt would have had me fitting something far too small. Measure the path, not the corpse.
While it was open I cleaned the flywheel rim and the motor pulley with isopropyl until the buds stopped coming up brown and did the head capstan and pinch roller at the same time. Old belt residue is what makes a new belt slip and then you're back in there next weekend wondering why.
Where it got to
What I can verify: it plays. A full side of a C90 straight through with no speed sag at the end which is where the take up torque is highest and where a slack belt gives itself away. Torque is strong enough that I can't stall the spindle with a fair squeeze.
(I tested it with a Simply Red tape that came in the same round of eBay buying and it sounds gorgeous in a way I wasn't braced for. Tone rather than content you understand, vintagely so.)
What I think happened: the belt hardened, shrank, snapped and the machine went in a cupboard.
I'd been ready for a second fault behind the first and for once there isn't one (so far at least!). I'll add an erratum here if the belt turns out looser than it feels in a month.
Cheers, Steve