Testing a MN3007

[blooze_man]

I have a couple MN3007s I got from a broken Rockman. Is there a way to test them to see if they're working?

[Scruffie]

Fix The Rockman and Put Sockets in it 

You'll need to make some kind of Basic BBD Circuit to test them in.

[Thomeeque]

 Hi!

You may try this:



Few notes:

• Use bigger value for C5 (like 150-220pF) to get to normal MN3007 clock range (it is just quick redraw of TZF3007 - TZF (short delay) module, where I am "overclocking" the chip to get shorter times)
• Preferably use multi-turn trimmer for RT1 for higher precision of V_Bias adjustments (value is not critical, let's say from 5k to 100k)
• C2, C3, C4 and C6 values are not critical as well, use anything around (like C2=100nF~1uF, C3=680pF~10nF, C4=1uF~47uF, C6=47uF~470uF)
• Same for the DELAY pot, bigger value will give you bigger range
• R6=270R was the lowest safe value where clocks were still ticking for me, maybe use bigger value (like 1k) to be safer..
• Don't forget to wire pins 7 and 14 of IC2 (drew separately as IC2P)

Usage depends on tools you have on hand. Sinus signal generator and oscilloscope would make it much easier and more effective, but in the worst case you can test it even by ear. Just adjust V_Bias to value according V_Bias-V_CC graph (e.g. to 3.7V for V_CC=9V), plug some signal (e.g. line-out from CD player, /bufferred/ guitar..) to the input and listen somehow signal at the output. You should hear same signal (maybe little louder, not quieter) as on input and it should audibly react to rapid movements of DELAY pot (slight pitch-shifting). If you hear quieter and/or distorted signal, you may try to fine-adjust RT1 (V_Bias), but it should not be too far from graph value (let's say in +-20% range)..

Good luck, T.

[Thomeeque]

Just adjust V_Bias to value according V_Bias-V_CC graph (e.g. to 3.7V for V_CC=9V)

Hmm, J.H./R.G. advice to adjust V_Bias approximately to 4.9V for V_CC=9V (in Ultra-Flanger project), so maybe I'm not understanding the graph correctly (I've got lost somewhere in V_DD/V_CC twisting probably )..

T.

EDIT: Correct value is probably V_Bias = V_CC - V_{Bias_from_graph} I did updated picture to v1.1 (reload page)..

[blooze_man]

Very cool. Thanks alot