Converting a Lab 80 to auto single play like an 80 Mk II
The main functional difference between the Garrard Lab 80 of 1964 and its successor model, the 80 Mk II of 1966 is that the 80 Mk II will automatically play a single record using the short, single-play spindle. The Lab 80 will not.
For a long time, I've been curious about converting a Garrard Lab 80 so that it would function like the 80 Mk II, while retaining the chaste, understated appearance of the original Lab 80, which I prefer.
With the introduction of the 80 Mk II, Garrard issued a revision to the original Lab 80 service manual, with additional operating instructions, part numbers and a bottom-side illustration covering the 80 Mk II. This revised manual has not yet been made available at Vinyl Engine or other online sources. One might think that the revised manual would indicate how to change one to the other, but although there were many part numbers that changed, not all of the changes were functional, to permit automatic single play. Some involved cosmetics such as the "turret" for the tonearm, the tonearm shaft itself, the platter mat and centre trim disc, and the control panel with its fluted tab controls. And as it turned out, some 80 Mk II parts with new part numbers were actually no different from their Lab 80 counterparts. Why different part numbers? I don't know.
I set out to convert a Lab 80 to automatic single record play. Starting with my own Garrard Lab 80 and a pile of parts from an 80 Mk II whose chassis was damaged beyond repair, it turned out that only four parts in the original Lab 80 had to be replaced with 80 Mark II parts, and what may be surprising is that the lever connected to the AUTO tab control is not one of them! There were a few additional parts from the 80 Mk II that had to be installed to implement the change.
Refer to the two photos of the undersides of a Lab 80 and an 80 Mk II. In the Lab 80 photo, the four parts that have to be changed are indicated with RED lines. In the 80 Mk II photo they are also indicated with RED lines and identified by the same names. 80 Mark II parts that must be ADDED are indicated with YELLOW lines and identified by name (the Reject Pawl, Pivot Pin and Circlip were already installed on the Manual Link).
Two critical parts are the Spring for Switch-Off Link and the Spring for Auxiliary Lever. It turns out that the strength of these two springs is important. Too strong a Spring for Switch-Off Link or too strong a Spring for Auxiliary Lever, and the "converted" unit will behave just like a standard, original Lab 80. If one had the original springs, this would be no problem but in my case, although I had a pile of parts consisting of all the levers underneath an 80 Mk II, I did not have the springs, which I had to wind myself.
The finished product performs just as desired. Pulling the AUTO tab starts the unit; the AUTO tab latches while the tonearm lifts, moves over the record to the proper diameter as set by the record size selector, and sets down. The AUTO tab then retracts automatically to a midway position. At the end of a record, the automatic mechanism lifts the tonearm off the record, returns it to its rest, and sets it down; and the unit shuts off.
