l0calh05t

it's not as if i didn't want all that equipment... there are many things i want... an oscilloscope (+ signal generator), a nice lab psu, a GOOD multimeter, a CNC machine, heaps of components for experiments... and i could go on and on...

so, what to do now? are the 0.9V correct? should i get a new 7805 or is it a waste of my time? anyone? ???

hrmm, i just connected it to the psu once more, and the voltage i measured behind the rectifier is now 0.9V, this can't be right... or is it?

hm, well there *is* that huge electrolytic cap right there where i was measuring... and charging that thing via my multimeter might actually take a looong time... nah, that statement just says i'm currently pretty fed up with circuits that don't work (and i never had that problem with my cables, those all lasted longer than any commercial one i bought, and the one that did break after two years of stage and practice (ab)use was really easy to repair)... ah, doesn't matter, in a few hours i'll be dreaming of building my own preamps, equalizers, compressors, microphones and synths again ;D EDIT: hohoho, i just measured the voltage across that cap .5V which is a pretty good sign that its probably charged (at least partially). hey, i'm beginning to feel better already! now i have some hope again that this thing might actually even work in a few weeks time.

one word... it starts with an f and ends with a k... i just removed the rectifier put in the one i had lying around and it conducts just fine between + and -... regardless of polarity. and i double, and triple checked for any solder going across two lanes... nothing. i think this is my first and last real diy electronics project. i guess i should stick with soldering my own audio cables.

i have 25€ on my bank account, 15 of which will be gone in a few days and 5€ in my pocket... so any investments are currently not an option... nope, don't have one, although i wish i did, so if anyone wants to donate one to me i'd gladly accept :P

the only way the rectifier could be connected wrong is if the writing on the rectifier is wrong, and as i mentioned, i think the fluctuating is the multimeter (it also fluctuates between 8.5 and 9.5 volts when directly at J1, and also fluctuates when i check a resistor by itself, as i said: its a piece of junk) well i have another one of those rectifiers lying around (for the SID board, but there's no point in starting to build that before i get the core in working order) so i might just try to replace the current one this evening and hope not to break that one as well...

ok i managed to desolder the 7805, or rather to desolder it a bit as the wick practically didn't seem to remove anything and tear it out. if it wasn't broken before i'm pretty sure it is now, considering how hot it became during the process and how hard i had to pull on that thing... >:( now, i conntected the psu, and checked the voltage between the + and the - pins of the rectifier. it seemed to fluctuate between 1 and 2 volts (the fluctuating may be the multimeter though as it's on of those sucky cheap ones) so yeah, i guess the retifier is fubar. (and probably the 7805 as well, and if not i don't know how i would manage to get it back in...) and with my luck i probably fried the single diode and the transistor as well

sure i'd like to have one of those, but i currently have just about enough cash to buy a roll of unsoldering wick...

or both are bad... considering my usual luck with these things this is probably what will have happened... i hope so too, now i just have to see how i manage to unsolder the 7805...

yeah, i was pretty sure 9vdc is what i was supposed to get. well, gotta get some unsoldering wick to get that damn thing out...

well, as i mentioned it is mounted exactly as it is supposed to with the + the - and the two ~ leads at the same place as shown in the schematic. between the + and the - (with 7805 mounted) there is a resistance of infinity, regardless of polarity, as mentioned in the first post, and where the voltage is marked 9v behind on your drawing is where i measured 0.5V (between 1 and 2 of the 7805) and where there should be 5v i measured 0. between the pins of J1 i measured an infinite resistance (or at least larger than 2MegaOhms, which is the highest my multimeter can measure) and between the two pins of J2 a resistance of 10.5kOhm. EDIT: I re-measured the + and - of the rectifier and although it displays infinity, when i switch polarities it displays a non-infinite resistance for a short moment, but i'm pretty sure i just charged the caps with my multimeter :P

i used a unit with four leads, and it is on the board just as it is supposed to according to the schematic. how am i supposed to disconnect pin 1 without removing the 7805 completely? ???

Ok, i just soldered everything onto the board and went on to the step where i check the voltages. 0V practically everywhere except directly at J1, where i get the 9V dc from my psu. trying to find out whats wrong myself i also found a voltage of 0.5V between pins 1 and 2 of the 7805, and a resistance of 1.5MegaOhm or just a few depending on polarity between two of the pins of the rectifier and infinite resistance between all other pins of the rectifier, regardless of polarity. what's wrong? did i fry the rectifier during soldering, or the 7805, or is it something completely different? edit: just in case it matters, it's one of the old core boards, with the quartz on the bottom