If you have a Beocord 3300 cassette deck that has stopped playing tapes or refuses to rewind you may be able to fix it. This post runs through how to change all three belts on the 40 year old Beocord 3300 and restore its musicality!

Warning: Don’t operate your Beocord with the case removed. Always unplug before attempting repair.

Intro

After several years sitting on top of my Beosystem 3300, I found time to plug in the matching Beocord cassette recorder to try and listen to a cassette. There’s no obvious way to open the aluminium flap and gain access to the cassette bay on the Beocord 3300. So if like me you have forgotten, just press the left hand front trim, next to PROGRAMMING, and magically it will open — it doesn’t need power, like the Beogram 3300, as there’s no motor drive for the flap.

Shows the left front corner with the label PROGRAMMING where you press to open the top flap and load a cassette tape
Press Programming to open lid, obviously

Having inserted a good cassette, unfortunately all I could hear was a thud, thud, clonk and no movement.

Some cassette decks are easier to service than this Beocord 3300 from Bang & Olufsen. Designed by Jacob Jensen in the late 1980s, the Beosystem 3300 offered futuristic styling and a change from the uniform 43cm black box stacks that graced many hifi enthusiasts shelves.

Unlike Jensen’s earlier designs, the 3300 is essentially a plastic case with aluminium panels and trim. As such it needs many fixings to join the upper and lower sections — so prepare some lids to collect the screws and note where they are used.

Replacing the belts

To access the belts, first remove all the fixings from the base and two at the rear. There’s no need to undo the two fixings nearest the heatsink. Next remove the plastic base cover. You should see the two drive belts attached to the motor pulley. The larger flat belt had detached on mine, as shown below.

Shows the Beocord's cassette mechanism and circuit board inside
Base cover removed – notice the flat belt is detached

Unfortunately, it’s not possible to change both without removing the cassette mechanism. And the third belt is hidden on top of the cassette mechanism, so you must remove the top cover and lid by undoing the 4 fixings inside.

Shows the cassette mechanism and top belt with the top removed
Top removed

Once the top is removed there’s a small, thin belt on top of the cassette mechanism which is simply to replace. I found a 25mm diameter, 1mm square belt from an assortment pack that stretched slightly between the two pulleys. Be sure to clean off any goo if your belt has melted, as many do. I use isopropyl alcohol or try hand gel sanitiser if you have no IPA.

The cassette mechanism, located on the right hand side of the unit is held in place by another set of 3 screws. All must be removed to access the lower plate that retains the flywheel. Underneath there are two belts, a 1.5mm square drive belt for the reels and a longer 4mm flat belt for the capstan’s flywheel.

Shows the flywheel housing with cassette mechanism removed
Access to change flat and drive belts

Using a wire hook the square belt is fairly easy to change. Note the route is rather odd, as shown below.

Routing for take up reel belt around right side of motor pulley
Take up belt route

The flat belt goes around the flywheel so you need to undo both fixings that hold the lower bearing. I loosened one end and removed the other to tilt the plate giving enough clearance to slide the belt under. A 135mm long belt seemed to provide enough tension without applying too much force on the bearing. My original belt had disintegrated – stretched with fractures in two places – so I found the right size replacement from an assortment.

You may well decide it’s better to order a replacement belt set for the Beocord 3300. I have done this in the past with mixed results and so I prefer to select the size from a universal set – see links below for suggestions.  These are typically available in sets of 50-100 so there’s a good selection for multiple players, especially useful for the local Repair Cafe.

Results

Before the belt change my Beocord 3300 had been covered in letters and papers acting more as an in-tray than vintage tech. Now it’s singing again and sounding rather good. With an HX pro head and fully automated via the remote control, having a working cassette recorder as part the Beosystem 3300 adds to its overall versatility.

Cassettes have become popular again so it’s worth dusting off these vintage machines and listening to them again – who knows what nostalgia it will bring?

Good luck with your repair and please leave a comment if you find it useful.

Useful links

Postscript

Increasingly I’m finding AI’s large language models are using (stealing) my content to provide answers directly in your browser. It seems good for you but ultimately bad for me. Why?

While I run this website to help others repair and fix items to avoid throwing them away, it takes time and effort to research and write. I welcome and need the feedback and questions that helps share how others encounter issues and helps improve the content for all.

Comments and feedback have all but ceased since the integration of AI search. So I ask myself why bother? Ultimately, just like many creatives and artists AI has ‘learned’ (stolen) from I think we will simply stop publishing on the Internet. And AI will then have to feed on itself and we all know what Darwin thought us about incest.

In effect, the AI industry has become valuable by using Internet content for free. Without consent or any renumeration to its creators. It’s wrong in so many ways and I guess ultimately the AI industry will have to pay one way or another. The backlash will come – just as it has for many technical revolutions.

But until it does this is the last post from Radio Retro.