|
Hi all
Thank you all for the tips, I made a mistake, and didn't check C42 at all...I missed it completely. I wasn't completely dead, but halfway there which is why the problem only manifested itself with the power supply fully loaded. With C42 and C61 replaced (C61 was fine, didn't make a difference) the ripple is now within spec on all rails (10mV or less). Two of the metal can transistors still get hot, but at least I can keep my finger on it for few seconds. The voltages are stable now. I have the color bars back, but my "Oven temp normal" still doesn't come on. There are +10V on one side of the lamp, but my TP1100 is still at 3.98V /g/TekScopes/photo/296482/3911053 There is a note in the manual, maybe it's also worth a try to check. Page 4-9 CHANGE TO: Crystal and Oecillator Oven Assemblies Because of the critical nature of the oven sub assembly, the entire assembly of the Oscillator Board, A10, and the Subcarrier Board, All, should be replaced as a unit if the crystal or oven fails. If crystal or oven replacement is attempted, the following pOints should be observed: 1. Silicone grease must be present between the temperature stabilizer and the wrap-around housing, Q1031, R1031, and R1035. 2. When reassembled, the oscillator board must not touch the wrap-around housing or either of the oven cover. 3. The crystal should not contact the temperature stabilizer other than at the welded flange around the crystal base. 4. When plugging the oven back onto the Subcarrier Output board, fit the oven, the two pieces of insulation, and the cover together; then attach to the Subcarrier Output board as a unit. This allows the spade lugs on the cover to align the Berg socket over the 6 square pins on the Subcarrier Output board. 5. To determine the oven operating temperature, a Leeds and Northrup 8693-2 Temperature Potentiometer with small thermocouple, or equivalent may be used. The thermocouple junction should be clamped between the temperature stabilizer and the crystal retainer. R1112, the branch of the temperature-sensing divider network, may be changed to move the operating temperature to 85¡ãC if component aging has seriously displaced the temperature equilibrium point. Normal operation will not be seriously impaired as long as the oven operates at a constant temperature at any point between 80¡ãC and 90¡ãC. 1 - if there was any grease it must have been dried up long time ago 2 - there is foam that is disintegrating between the inner oven and outer housing so probably also worth checking 5 - is probably worth checking. My multimeter came with a thermocouple or what do you think shall I check next? |
