EOS 600 series (620, 630, 650)
From Silvergrain Labs
EOS 620 and 630 are early Canon EOS autofocus cameras. In used market, they are usually traded well below $100 a piece. The autofocus performance is inferior to EOS 3 or even Elan 7, but they have excellent viewfinder screen and they are very practical cameras.
One of the most common problems of EOS 600 series is draining battery. This is said to be caused by leakage current of the backlight power system. This power system is connected to the battery before the power switch, and therefore, a new lithium cell is completely drained in a day's time regardless of the power switch position.
It may be possible to identify the faulty part and replace it, but there is a quick fix. It is easy to access to the place where the backlight power supply is connected to the main power supply board at the bottom of the camera. Remove the grip (battery holder) and the bottom plate. You'll get a view like the following:
(Click on Os to blow up.) This is from a 630. You see TP1, TP2, TP3 and TP4 on the right side of the power supply board. TP1 and TP4 are connected to the battery on the right, and TP2 and TP3 to a shielded wire. Remove the TP2 and TP3 (the middle two) from the pins from the circuit board and insulate with electric tape. After removing the middle two wires, it should look like the following:
This is from a 620. Once this mod is performed, the battery can be left in the camera and won't drain for months, as long as the camera is turned off.
EOS 620 has a faster X-sync speed (1/250), while 630 has a faster motor winder and custom function capability, and somewhat faster autofocus engine. However, 620 is a better buy, as long as the spec is sufficient. 630 uses a rubber shutter bumper, which is largely deteriorated by now, and causing sticky shutter problems. I am yet to see a similar problem with 620.
PS. Robert Jäschke used to have web pages (in German and another one in English) describing this problem but I can't find them on google as of today, and I also remember that his pictures weren't very clear about which wires to unsolder. So I only meant to provide a bit of additional info in this page.
EOS 620
Shutter speed down to 1/4000, X-sync at 1/250, AEB function, plesant shutter sound.
Custom Functions (EOS 630)
１ 自動巻き度しの抑止 ２ フィルム巻き戻し時に端をパトローネから出しておく ３ ＤＸコードを無視する ４ 親指ＡＦ（部分測光ボタンを押すとAFが機能する） ５ マニュアル露出時に絞りと速度の操作を逆転 ６ 手ブレ警告音の抑止 ７ ＡＦ合焦後にＭＦに移行可能
Shutter speed down to 1/2000. X-sync at 1/125.
6-zone evaluation metering. AF from -1EV to 20EV. Viewfinder coverage 94%, magnification 0.80x.
