Jump to content

ExtraThiccBoi

Members
  • Content Count

    16
  • Joined

  • Last visited

Community Reputation

2 Neutral

About ExtraThiccBoi

  • Rank
    10+ Post Club

Profile Fields

  • Location
    Void of darkness

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

  1. Hi, got a problem with my amp, recently completely restored. There is a hum if no inputs are connected, if i short them, the hum goes away. If i connect a source, the hum becomes very quiet. I run just the main amplifier PCB, disconnected all of the other boards like phono or tone. Chassis is grounded (continuity checked). Anyone got any ideas what to do? Thanks Dave
  2. Hi, i stripped my HK6500 from all peripheral boards, running just the power board fed directly from Pre-out on my Magni 2 Uber. The power amp board doesn't hiss, but it hums a bit. Its audible only at point blank range from the speaker. I can not tell if its 50Hz or 100Hz, i tried feeding the hum to my PC but the noise floor is too high to tell the hum itself through a spectrum analyzer. I've changed all Elec capacitors and reflown most joints on there and am starting run out of ideas. Its uses a center-tapped trafo with negative and positive PSU rails. It hums louder when it's cold, after 15 mins or so, it becomes quieter My idea was to try running just half of the transformer and put the common ground to mains earth, but i dont know if it could hurt anything. My other idea is the new filter caps i got were old too, they are 12000uF 80V Nippon SMH with code 7DUH9M. Thanks for any help!
  3. Okay, this is unrelated to capacitors,but i dont wanna start a new thread. On the main amplifier board, there are 4 pairs of TO-92L BJTs. The PCB is lightly discolored under them and before i took the amp apart, i noticed they run at like 65-70°C. I think they are the pre-amplifier transistors. Do you think they run hot because i feed the amp too high signal? The CD input sensitivity is 0.150V, but all of my gear outputs atleast 1Vrms. Is that anything harmful? I dont wanna lower the digital volume since it screws up with quality.
  4. I have cleaned many, many things with IPA and ethanol. Both are basically harmless to 80% of plastics. By the way, this white gunk is the rosin dissolved in isopropyl alcohol. I have cleaned the main PCB of the amp with IPA and had none of these nasty residues. Isopropyl is the only strong solvent i know of that doesnt directly damage or dissolve plastics.
  5. I've been told the rosin can absorb moisture over time and create a high-resistance path.
  6. What do i use to clean off the flux then? Some people use acetone, thats too aggressive and could legitimately damage these old PCBs. Isopropyl is more gentle but still very effective
  7. I check every joint i make or fix with mm continuity, all of these are fine. I am concerned if i didnt use too much solder. This is what happens when i clean the board with isopropyl. It dissolves some goo the pcb had from the factory and makes this nasty mess
  8. You're right. I'll put in the panasonics/the ones which measure better. Also, i don't have much experience with pcb soldering, are these joints adequate?
  9. Ill try them and if i decide they're bad ill take them out
  10. So i got the measurement thingy, the nichicon 100uF 25V throws 94uF and 0.79ohm ESR. The panasonic 100uF 25V i got as backup measures 102uF and 0.04ohm ESR. Which one should i put in? The audio grade or the lower ESR one?
  11. Yeah, well, the shipping from US suppliers to EU is expensive. The cap should be gold, this is just black and white image, even if you check the UFG on mouser, it has black and white image too.
  12. So yeah, i ordered one of those Mega328 based testers so i can test the caps and all the transistors. The amp better be restored properly than blow up after few months because of my stewpidity.
  13. Unfortunately no, but i know the CEO of the supplier i got them from i can ask there.
  14. In some european countries, especially the less developed ones, loads of NOS vintage semiconductors can be found. I managed to find the output transistors NOS from Germany and in Croatia, there is a guy who sells those NOS too, he even smashed some of them open to prove they're genuine. The thing is that from mouser, i'd pay 15 USD for the parts, 30USD for shipping and then additional taxes and import fees. I bought the rest from big german supplier so i am sure those are all genuine.
  15. I checked both of those using the number provided and both match the cap's size, markings and the specs. I'll try to contact nichicon, thanks for that tip These are not fine gold, these are the lower ones (UFG -> UFW). They also were not cheap, i paid (in US $) around 0.2 for the bigger ones and 0.15 for the smaller ones. https://www.digikey.com/product-detail/en/nichicon/UFW1E101MED/493-15125-ND/1964118 This is the official digikey site.
×
×
  • Create New...