resurrected my tascam porta 05

(Update: 9/9/2020 – higher resolution images)

Tascam Porta 05

Decided to dig out my old Tascam Porta 05 ministudio in order to digitise some old 4-track recordings. But, found that the play heads seemed to be stuck in the forward position. Full symptoms and notes:

• Power on ok
• Impossible to insert a cassette due to the position of the heads
• Can hear the motor (which turns all the time power is on – this is normal)
• Motor responds correctly to the pitch control
• Fast forward button works – spins the central right capstan
• Rewind button works – spins the central left capstan
• Tape heads in forwards position, but the rubber wheel in front of the stop button is not forward enough to press against the metal capstan
• The metal capstan, which should normally be spinning all the time the machine is powered is not actually spinning
• Pressing play or record buttons does nothing – the central capstans that would fit into the tape spindles do not turn

I did google around trying to find a solution. I did find a couple of people with the same problem, but no solution posted. I googled for the service manual with no result other than someone in the states selling on ebay for around $22. I wish companies like this would get their service manuals PDF’d and onto the web – shouldn’t be an issue for what is essentially obsolete equipment?

Anyway, with no solution available from the outside, I decided to take a quick look inside to see if there was anything obviously out of place. Getting inside is easy:

1. Remove the 5 screws from the back panel
2. Carefully part the two sides noting that:
   • The power on/off slider will likely drop out as it detaches from the internal control
   • all the other sliders remain with the top of the case – but some detach in the process from the underlying control which remains in the base.
   • In my case the forward position of the tape heads was preventing the sides from separating. Pressing them back by pressing the plastic between the erase and write heads made enough space.

Inside the Tascam Porta 05

Close-up showing heads fixed forward

With the sides parted, I then powered up and observed the mechanics when pressing the various control buttons. I couldn’t see anything obvious, but then noticed that underneath the controls is a flywheel attached to that capstan in-front of the stop button. The flywheel is belt-driven and was not spinning.

Nudging the fly-wheel with a cotton-bud.

Using a cotton bud, I gave it a few nudges, attempting to pushing it round in either direction. I was quite surprised  after a few attempts when the belt picked up and the flywheel turned under the power of the motor. At the same time the heads snapped back into the retracted position, and the play and record buttons now worked.

All that remained was to give it a good clean-out and reassemble. Taking care to align the Record function sliders with their underlying controls, and get the 5 screws back in, and I am back in action with kit that I thought was pretty cutting edge back in 1987.