AST-3G Plus II

AST-3G Plus II
Preliminary Information
Release Year	1987
Leak Risk	Medium
Batteries	None
Mounting Technology	Through Hole
Capacitor Types	Aluminum Electrolytic, MLCC
Destructive Entry	No

For more information, see this article's corresponding Wikipedia page: Device.

This device is in the WorkNeeded:OriginalParts category because it was flagged as missing information on the original parts. It may have replacement parts listed but those cannot be assumed to be identical to the originals. If you have a list of the original parts, please feel free to add them by copying the relevant table from EditorsToolbox:Tables

This device is in the WorkNeeded:General category because it was flagged as missing general information about the device. The information may be incomplete, using default text, or inaccurate and should be verified with external sources if possible. If you can add or correct information on this page, please feel free to edit it and do so.

Jumper settings and other info here

Known Issues

Three electrolytic capacitors are leaking, try to replace

Causes

Produced in 1987, electrolytic capacitors are prone to leakage

Solutions

Recapping

Disassembly Notes

The leaked electrolyte corrodes and causes solder oxidation, which makes it difficult to desolder. Be careful to avoid high temperature damage to the pad

Original Parts

AST-3G Plus II (C)AST 1987, FCC ID: DJK 68Y AST3G

PCB Mark: 202161-303A Silkscreen: 202161-003

Capacitor Specifications and Footprint Information
RefDes	Qty	Capacitance	Voltage	Mount	Diameter/Size	Height	Lead Spacing	Temp	Type	Brand	Series
Others	23	100 pF		Through Hole			2.0 mm		MLCC	104
C35	1	2.2 pF		Through Hole			2.0 mm		MLCC	222
C26, C27, C28, C29, C30, C31, C32, C33	8	47 nF		Through Hole			2.0 mm		MLCC	47K
C1, C2, C3	3	22 µF	16 V	Through Hole	5 mm	5 mm	2.0 mm	85 °C	Aluminum electrolytic	ELNA	018 H

Integrated Circuits
RefDes	Qty	Model Number/Part Number	Manufacturer (If Applicable)	Explanation	Datasheet
U1, U2, U3, U4, U5, U6, U7, U8	8	KM41C464P-10	Samsung(?)	Dynamic RAM	Memory Guide
U9	1	P82C435	CHIPS	Enhanced Graphics Controller	Link(click link, then click the download icon)
U11, U12, U13	3	DM74LS244N	National Semiconductor	Octal 3-State Buffer/Line Driver/Line Reciever	DM74LS244
U14	1	LM339N	National Semiconductor	Quad Differential Comparator	LM339
U16	1	74LS153N	Signetics	Dual 4-Line to 1-Line Data Selectors/Multiplexers	SN74LS153
U17	1	74LS151N			DM74LS151
U18	1	SN74LS74AN	Motorola		SN74LS74A

Replacement Parts

0805 SMD 22uF 16V - 50V 10%

The lead spacing is too limited, I'd like use SMD on back of PCB where the through holes are filled with solder.

Capacitors
RefDes	Qty	Compatible Part Number	Order Links
			Digikey

Through Hole Capacitors

Capacitors
RefDes	Qty	Compatible Part Number	Order Links
C1, C2, C3	3	ECE-A1CKS220 / 25MH522MEFCT56.3X5	DigiKey Mouser LCSC
C26, C27, C28, C29, C30, C31, C32, C33	8	K473K15X7RF53L2 / CD1H473KC9BER1E100	DigiKey Mouser LCSC
C35	1	FG28C0G1H2R2CNT06 / 561R10TCCV22	DigiKey Mouser LCSC
Others	23	K101J10C0GF5UH5 / CC1H101KC1EDSL4B1100	DigiKey Mouser LCSC

Integrated Circuits
RefDes	Qty	Compatible Part Number	Order Links
U11, U12, U13	3	SN74LS244N	DigiKey Mouser LCSC
U14	1	LM339N	DigiKey Mouser LCSC
U16	1	SN74LS153N	DigiKey Mouser LCSC
U17	1	SN74LS151N	DigiKey Mouser LCSC
U18	1	SN74LS74AN	DigiKey Mouser LCSC

If parts are not available or different selection is preferred, you can use the values in the Original Parts section to perform a parametric search.

Kits

Digikey BOM: https://www.digikey.com/

References