![]() I would have socketed and replaced the TL594 as well. You are lucky that the failure of Q9070 did not propagate through the drive transistor and diode into the switching regulator controller. Won't show channel 1 on its own Only shows both or channel 2. Am going to inspect all remaining resistors in the HT section. Have since isolated to the multiplier and have ordered a replacement one. If anyone has some advice or ideas here I'd appreciate it. RS don't have any suitable replacements until mid December so I will shelve that problem until then. This was occurring before I did any refurb work. I have done some googling and looks like it may be the 510K resistors in the HT chain (known problematic) or the z-axis or the multiplier. Intensity flicks in and out a little bit. Bit of intensity flickering Not sure what this is yet. Replaced capacitor with low ESR one and it's fine now. I will replace that once I get the preregulator working. I used a standard cheap ass 33uF cap on that instead of a low ESR type. There is a lot of switching noise there, above min specification. Noisy 100V line This is a cock up on my part. Substituted above parts in and it worked. As a precautionary measure C907 is being replaced with a Vishay MKT1813 1uF 630V unit I will lap solder the connections onto Q9070 and shrink it as the original connector was damaged by the explosion. CR907 is being replaced with a STTH2R06 ultra-fast rectifier. Also known compatible as some units shipped with them in. Crap by modern standards but cheap and with a higher voltage headroom and similar characteristics to the original device without being too daring. Pre-regulator exploded The pre-regulator MOSFET Q9070, an IRF710 exploded. I applied 43V across TP940/950 to bring the scope up on DC and it came up fine. After this explosion, I tested the pre-regulator mostly worked by applying 22V across C925 to see if the SMPS controller was still working. Took the driver transistor out and a diode. About 30 minutes after power up, the IRF710 in the preregulator blew it's arse out. A sticker will go on the back of the unit saying these need to be replaced in 10 years. I replaced the RIFAs with NEW Kemet RIFAs. Pretty good condition: First step I did was empty it of the ageing electrolytic capacitors and mains filter: New high quality Panasonic and Rubycon parts were substituted in. Decided to do a full refurb on it as these are known to be occasionally dodgy as hell. Powered it up, seemed ok bar a couple of issues. Described as working, which it mostly was for a bit so no complaints there. Bought a 2235 from a hamfest type event for a whopping £25. Thought I better break this off the TEA stuff so it's easier to find if anyone else comes across it. ![]()
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